- "Did you ever think about why I chose the name Prometheus? He challenged the omnipotence of the gods. You see, because, like you, they play judge, jury, and executioner. But Prometheus took away their power."
- —Adrian to Oliver Queen[src]
Simon Morrison (born c.1986), known under the alias Adrian Chase, is the former District Attorney of Star City and a former close collaborator/friend of Oliver Queen as mayor, helping him in cleaning up the streets through the legal system. He is the serial killer who calls himself Prometheus, and not only knows that Oliver Queen is the Green Arrow, but has a personal vendetta against him as well. Having lost his father four years ago at the hands of The Hood, Adrian desired retribution, and spent his time afterwards studying The Hood's skills and history, while also uncovering Oliver's true identity as the Green Arrow. In his alter-ego, Prometheus crusades against the Green Arrow in order to destroy the hero's life and legacy. He has also been labeled by the media as the "Throwing Star Killer" for murdering people whose names formed anagrams of individuals on the List using shuriken made from Oliver's discarded arrows as a form of sending a twisted message to him.
Simon was born sometime around 1986 to Justin Claybourne and an unnamed woman with the surname Morrison who would later change her name to Amanda Westfield. While raised by his mother Simon still knew and loved his father and was very close with him. Justin even kept a photo of him as a baby in his office.
Preparing for his crusade against Oliver Queen
In 2012 Simon's father was murdered by the Hood, and so he sought vengeance upon the elusive vigilante. Dropping off the grid completely and erasing all traces of his existence from the internet, and changing his name to "Adrian Chase". Adrian researching his target and learned everything he could about him. In his research, Adrian discovered the identity of his target as Oliver Queen and obsessively studied him, learning everything he could about him and his allies. In his research he became aware of the existence of The List, a book of Starling City individuals with ties to Malcolm Merlyn, which included Adrian's father who Oliver had targeted. This led to Adrian believing that Oliver was really a serial killer who's life poisons others, and his righteous crusade was a lie to justify a killing spree and swore to make him suffer. Adrian continued to study and observe Oliver and his allies without their knowledge for 3 more years until he was confident he knew Oliver better than he knew himself.
In early 2015 after learning everything he could about Oliver, Adrian wasn't fooled by Roy Harper's deception, faked death, and confession to being "The Arrow", and continued his agenda. Adrian then sought out Oliver's former mentor Talia al Ghul to learn the ways of the League of Assassins. Impressed that Adrian deduced Oliver's identity on his own Talia accepted his request, as she was now equally vengeful towards Oliver as he had killed her father Ra's al Ghul. After acquiring the skills needed from Talia, Adrian armed himself with an array of weapons forged from The Hood's discarded arrows kept in the Star City Police Department evidence lockup. Adrian also began using a suit strikingly similar to Oliver's suit from his days as the Hood, but with darker colors and with a full face mask, adopting the name "Prometheus". Adrian chose that name because of Prometheus' role in Greek mythology in taking away power from the judge, jury and executioner gods. Returning to Star City, Adrian became a lawyer to give him better access to government information to aid in his crusade. At some point he met and fell in love with a woman named Doris, who later became his wife.
At some point, Adrian also became aware of the existence of time travel and the multiverse and even knew about Team Flash's pipeline prison, indicating that he may keep tabs on Barry Allen/The Flash as well. He was also somehow aware of the Legends and the Waverider indicating he has somehow kept tabs on them also. It's possible he knew researched their movements through history like Nate Heywood did, or learned of them from Talia who met a time displaced Sara Lance/White Canary in 1960 as a child. He also became aware of Oliver's son William. It is possible that he gained this knowledge from Evelyn Sharp when he turned her to his side, as she was part of Team Arrow during the Invasion event which dealt with many of these subjects.
Sometime after Susanna's death, Adrian succeeded her as the district attorney of Star City. Adrian was building a case against Derek Sampson with the intent of flipping the drug dealer so he'd give up the names of his suppliers.
Beginning his crusade
Five months following Damien Darhk's death, Adrian began his crusade by targeting individuals in Star City whose names formed anagrams to other names on The List. His first target was Lieutenant Conahan. When Conahan was leaving the SCPD precinct, he noticed Prometheus on the rooftop. Mistaking him for Green Arrow, Conahan asked if he could help him, but was shot by an arrow. Conahan painfully tried to shoot back, but Prometheus dodged his shots, leaped to the ground and threw a shuriken to disarm him. As Conahan tried to flee, Prometheus threw a knife into his leg, knocking the cop down. As Conahan desperately tried to crawl away, Prometheus slowly walked up to him, sword in hand, and, when asked if he was Green Arrow, coldly replied that he wasn't and killed him.
Conflict with Tobias Church and meeting Oliver Queen
A few nights later, Adrian learned of Green Arrow's encounter with crime lord Tobias Church amidst his illegal deal with AmerTek Industries, where he almost killed Green Arrow. In response, Prometheus stalked Church and as he left Club XLR8, and killed his two bodyguards. While Church mistook him for the Green Arrow and laughed in amusement, Prometheus threw an axe into Church's shoulder, leaped to the ground and slammed Church into the pavement. Prometheus angrily told Church he was aware of his attempt to kill the Green Arrow, and warned Church that the former was his to kill and if he ever tried to do it again, then he'd die as well. 
After learning that Oliver's ally Rene Ramirez supposedly killed Derek Sampson, Adrian went to confront Oliver about it (officially becoming acquainted with him) and told him about what happened to Sampson. After Sampson turned out to be alive, Adrian asked for Oliver to get Judge Pittson to allow Adrian to obtain a warrant to search his known hideouts. After he agreed, Adrian told Oliver about the first time they met, when Oliver picked up his girlfriend, but he ironically reassured Oliver that he doesn't hold grudges. Later, Green Arrow and his new team apprehended Sampson which pleased Adrian as he informed Oliver and Thea of this.
A few days later, during a meeting at the mayor's office, Adrian met the new deputy mayor Quentin Lance and said that working for him would be a pleasure. While Quentin was surprised Adrian told him that he doesn't blame Quentin for working with Darhk, as he had threatened his daughter Laurel. He explained public service wasn't easy and that, sometimes, getting a little dirty was inevitable in order to clean it up. When Team Arrow apprehended Sergio Espinoza, an associate of Tobias Church, and stole a package from Palmer Technologies, Adrian and Quentin personally delivered it to the SCPD evidence locker. The evidence instead turned out to be a disguised bomb, causing an explosion that allowed Church and his men to infiltrate and steal weapons from the evidence locker. 
Later that night, Adrian interrogated Espinoza at the Anti-Crime Unit headquarters, threatening to beat the information out of him due to Espinoza's refusal to talk. Initially, Espinoza didn't take Adrian's threat seriously due to his position as a district attorney, but Adrian reminded him that justice in Star City is dealt by vigilantes. Before the interrogation could go further, Church and his men attacked the ACU and killed several of the guards all while trapping Adrian and Espinoza inside the building. Suddenly, Ragman appeared and planted a bomb on the wall, and as he absorbed the ensuing explosion, Mr. Terrific, Wild Dog and Artemis emerged from the hole that was created. The team escorted Adrian and the other ACU members out of the building to safety. Later, Adrian informed Quentin and Thea of the incident but hadn't been able to find Wild Dog, who had been kidnapped during the attack. Adrian then told them that he'd re-evaluated his view on vigilantes and started to trust Team Arrow more.
Angry that Church had ignored his warnings and kidnapped Wild Dog, Prometheus confronted Church, and while attempting to kill him with an arrow, Church's bodyguard protected him from the attack. Prometheus reminded Church he had his second warning and wouldn't be given a third and left. After Church was arrested following his defeat by Green Arrow and being transferred to Iron Heights, Prometheus attacked the convoy of police cars escorting him. After slaughtering the escorting officers, he confronted Church in the police van. Church futilely tried to plead for his life by telling him Green Arrow's identity: Oliver Queen, unaware Prometheus already knew. When Church asked if they were cool, Prometheus threw a shuriken into his neck and killed him, and replied that they were, then left the scene of his slaughter.
Waring with Team Arrow
With Green Arrow now aware of his existence after being informed by Church prior to his death, Prometheus lured him and Spartan to a construction site, using Church's cell phone to lure them out. After they tracked the phone, Prometheus called it, heavily breathing into the phone, as Green Arrow answered. He then ignited a message on the ground, "SO IT BEGINS". From there, Prometheus continued killing civilians to form more anagrams of individuals on the List including Peter Meld and Gay Eked. Their names, along with Conahan and Church's, all spelled out anagrams of Green Arrow's previous victims: Adam Hunt, Ted Gaynor, Palmer Cokes and Sachi Beech. Adrian later went to the scene of Gay's murder where he "met" Green Arrow and told him everything he knew about the victims, Green Arrow oblivious that his target was speaking to him.
Later Susan Williams reported on Prometheus' killings on the news which Adrian told Oliver was a disaster. After Susan dubbed him the "Throwing Star Killer", Adrian admitted to a annoyed Oliver that it had a "certain flare" to it. Finding more six more potential victims after discovering Prometheus' pattern, Team Arrow sent a member to each one. Prometheus went after a train driver but was confronted by Artemis. They entered into a duel where Artemis managed to cut Prometheus' right arm, before Green Arrow came to Artemis' rescue, shooting an arrow into his back. Instantly recognizing it as an explosive arrow, Prometheus threw it onto the roof where it exploded and Prometheus escaped through the hole made, but left a bomb which blew up the train, though Green Arrow and Artemis ultimately escaped with the train driver. Later, Prometheus sneaked into Quentin Lance's apartment and left a cut on his right arm, while he was passed out from alcoholism, just like the cut Artemis gave Prometheus, and left a shuriken to implicate him.
Sometime after Prometheus' encounter with Artemis he sought her out, after deducing her identity as Evelyn Sharp. Prometheus manipulated her into betraying Oliver, as Evelyn had become resentful of him after learning he was the Hood, who'd murdered several people she knew, promising to let her watch when he finally killed Green Arrow. Recruiting Evelyn to his cause allowed Prometheus to learn the identities of every Team Arrow member, as well as information on their personal lives including loved ones. While trying to find bank robber Eric Dunn before the elusive Vigilante did, Adrian interrogated his arrested associate Laura Buser. However, she simply told him to go to hell to which he gave a cold stare and replied that he'd been to hell, and slammed his hand into her mask to intimidate her, and so she gave up Eric's location. As Adrian told Oliver that Eric was hiding out at Papp Motel and Oliver went to inform the ACU while Adrian secured a warrant to search the area. Later after Team Arrow defeated Vigilante, Prometheus met Artemis alone on a rooftop, where she assured him she wasn't followed and told him that Team Arrow didn't suspect her true allegiance.
In December 2016, Prometheus went to Central City, where he broke into S.T.A.R. Labs without setting off any alarms and freed Laurel Lance/Black Siren, the Earth Two doppelgänger of the late Laurel Lance/Black Canary, to impersonate her Earth One counterpart to taunt Oliver as he loved her Earth One counterpart. Threatening to kill her if she didn't comply Black Siren, reluctantly, agreed and, to maintain her cover, Prometheus told her vital information on Earth One Laurel's life. He also informed her of the Waverider and the Legends, so Laurel could use the cover story that Sara brought her back and transported her to the present. Team Flash would be unaware of the breakout for almost 3 days.
First encounter with Green Arrow
During Christmas, Prometheus, while sharpening his weapons in his hideout, was approached by Evelyn with photographs and addresses of Felicity Smoak and Rory Regan. Evelyn then asked Prometheus to be there when he killed Oliver, but Prometheus stated that he didn't intend to kill Oliver, only to make him wish he was dead. Prometheus later attacked Curtis Holt at the mayor's Christmas party and his husband, Paul, effortlessly defeating him and injecting him with the drug, Dycloseral, making Oliver and Team Arrow aware that he knew their secret identities.
At Claybourne Pharmaceuticals, Prometheus confronted Green Arrow and engaged him in a battle, managing to hold his own for a bit and showing off a technique Talia had taught them both. Suddenly, Wild Dog shot his katana out of his hand, causing Artemis to intervene and reveal her true allegiance. As Green Arrow and Wild Dog stood in shock, Artemis fired a smoke arrow to cover her and Prometheus' escape. While investigating Claybourne Pharmaceuticals, Detective Billy Malone discovered a photograph of a baby and sent it to Felicity, before Prometheus apprehended Billy. Adrian later told Oliver of Billy's abduction and insisted that the ACU have a shoot to kill order placed on Prometheus which Oliver agreed to. Tracking Prometheus to the AK Desmond Group, where Oliver killed Claybourne, Green Arrow discovered that Prometheus had staged the hallways with bodies to recreate the scene of Oliver's victims he'd killed when pursuing Claybourne before confronting Prometheus in the exact spot in which he killed Claybourne. Prometheus asked if the Green Arrow had even hesitated when he killed him, or he was merely another name on the List, but as Green Arrow told him he was there if he wanted revenge, Prometheus replied that his crusade was about so much more than simple revenge.
They engaged in a fight before landing crashing into one of the building's floors. Secretly over a wireless speaker, Prometheus told Green Arrow that he knows everything about him and is going to show him and everyone else that everything he touches dies. Having dressed Billy Malone in his suit beforehand, Prometheus managed to trick Green Arrow into killing him in order to prove his point, telling him over the wireless speaker, attached to Billy, that everyone he loved would die. Somehow, Prometheus also imitated Lyla Michaels' voice to trick Diggle into returning to the safe-house his family were staying in, and tipped off the F.B.I. which allowed them to recapture him. After this, Prometheus sent Laurel to impersonate her Earth One counterpart, roughly 3 days after breaking her out of S.T.A.R. Labs.
Exonerating John Diggle and working with Black Siren
Eventually Laurel's cover was blown but as she asked why she couldn't have just killed them, Prometheus furiously tackled her. Choking her throat tight enough to prevent her using her scream power against him, Prometheus reminded her that her freedom and life were contingent on her following his orders. Terrified, Black Siren agreed and fell in line. Adrian was later called to Oliver's office where he informed him of John's arrest, as he'd been wrongfully imprisoned for illegal arms dealing of a nuclear trigger, set up his superior General J.G. Walker, and wanted Adrian to represent him. Adrian was initially skeptical but agreed. Adrian visited John and told him he was representing him but as Walker appeared to transport John into custody, he insisted to Adrian that Walker would simply falsify an excuse to kill him to cover his tracks. Adrian then tried to delay Walker with various regulations but Walker told Adrian he had the attorney general on speed dial, and threatened to have him disbarred unless John was placed in his custody within 24 hours.
Later Black Siren escaped Team Arrow's custody and Prometheus went to meet up with her. Encountering Ragman, he quickly knocked him out before confronting Green Arrow, which lead to another fight between the two. Green Arrow threw a drugged-dart at Prometheus before firing a cable-arrow at him, hoping to restrain and finally capture him. Instead Prometheus shrugged off the drug and reacted quick enough for the cable to wrap around his arm rather than his whole body as intended. Breaking the cables with his sword, Prometheus told the archer he had a tolerance to the drug and they continued their fight. After seeing Felicity being confronted by Black Siren, Prometheus tauntingly told him to choose between him or Felicity, concluding the ordeal by kicking Green Arrow through a wooden wall, to where Black Siren and Felicity were, before escaping as Black Siren was captured again.
To ensure John wasn't placed in prison, Adrian told John to punch him and pretended to try and fight back as his guards restrained him, having instructed them to, as Walker saw this happen. Adrian then reminded him that if a prisoner committed an offence against the district attorney within his jurisdiction, he could personally oversee the matter and reminded Walker it "could take a while". This allowed Adrian to delay John's transportation into Walker's custody by one week. Adrian discovered from a friend at the National Security Agency they were investigating Walker including his involvement with the nuke, but Walker's associates made sure the information remained classified and beyond Adrian's reach. Later, Adrian received the NSA's case against Walker from an anonymous source, and after sending it to a judge pleaded for a motion to dismiss, and was able to get John released on bail.
Oliver later held a conference to make John's exoneration public and to commend Adrian's actions. Susan Williams hoped to get an exclusive on Billy Malone's death, though Adrian told her he had no comment as he'd told the other reporters. After a gunman attacked City Hall and shot Adrian, he was taken to hospital but recovered quickly, though Doris was concerned about his well-being and tried unsuccessfully to convince him to take some more rest instead of come immediately back to work. After discovering the shooter as James Edlund, a man who had lost his family to a mall shooting years before, Adrian discussed people's rights to wield firearms with Oliver. Though skeptical to allow civilians to have easier access to firearms, Oliver eventually agreed with Adrian and after much discussion with councilwoman Pollard adjusted the firearms law, allowing people better protection.
Attacking the Queen administration
After Oliver visited Adrian's mother Amanda, asking her for the name of her son, Adrian sent a letter to SCPD Captain Frank Pike containing the autopsy report for Detective Malone's true cause of death. As a result, Pike ordered the Anti-Crime Unit to arrest Green Arrow for Billy's death. Adrian was later present when Oliver and Quentin tried to convince Pike that the Green Arrow was innocent, though he initially refused to listen as he'd still killed a member of ACU. Despite this, Oliver was successful in getting Pike to stop his pursuit after talking sense into him. After this, Adrian leaked the mayor's office's role in covering up Billy's death to the media which was then broadcasted by Channel 52 News, in order to end Oliver's administration as mayor.
Discrediting the Green Arrow and Oliver's discovery of his identity
Adrian offered his letter of resignation in order to take full responsibility for the cover up, but Oliver denied his request and instead insisted that Adrian represent him as his lawyer at the hearing. While Adrian agreed, he reminded Oliver that the circumstances would call for someone to take the fall. At the hearing, Adrian and Oliver watched as the coroner confessed to filing a false report on Billy's death to Councilman Collins, and as Captain Pike told them of Oliver's vouching for the Green Arrow. After the first stage of the hearing, Oliver, Thea, Quentin and Detective Dinah Drake left for the office, though their limo was attacked by Vigilante which left them all injured. Adrian gave his reassurances to delay the hearing in light of the attack, while making Oliver accept medical treatment as he'd declined. Adrian confronted Dinah as she'd found a broken piece of Vigilante's visor and offered to take it back to the precinct for her.
Later, Prometheus encountered Vigilante on a rooftop, presumably using the tech from the visor to find him, and warned him that Oliver was his to kill, though Vigilante simply swore to kill him first and they came to conflict. Prometheus, clearly being the superior combatant, overpowered Vigilante and forced him off the rooftop, though somehow Vigilante survived and fled. Unmasking, Adrian then called 911 and informed them of a Vigilante sighting. Later Adrian talked to Pike over the various vigilante sightings and if they were simply delaying Star City's inevitable fate, though Adrian reminded him that delaying the inevitable was part of their job. As he kept Pike busy with small talk, he slipped the piece of Vigilante's visor back to Dinah.
At Oliver's office, Adrian offered to take the fall for everything, but Oliver refused to accept this, though Adrian reminded him that someone needed to be discredited or Oliver would lose his job. Instead, Oliver decided to offer up the Green Arrow. Adrian stood by Oliver, Thea, Quentin and Dinah as he gave a speech to the public discrediting Green Arrow with the murder of Billy Malone. Afterwards, Adrian informed Oliver that after his speech Collins has ruled against ending Oliver's administration. Oliver immensely thanked Adrian for this and Adrian reassured Oliver that he didn't do it just because he was his boss, but because he was a friend. Later, Adrian confronted Susan and told her he supposedly had an exclusive for her, sickly joking that it was a "matter of life and death".
After confronting Susan he kidnapped her and held her in an abandoned hotel rigged with explosives. Prometheus then filmed her tied to a chair and tearfully screaming in fear, as he held a knife to her throat, tauntingly telling her to scream for him again. Anticipating that Team Arrow would use his mother against him as leverage, Adrian had Amanda relocated and left the film of him and Susan playing on a continuous loop for Team Arrow to find. Adrian was later informed by Talia that Oliver was aware of his true identity as she had told him to make him suffer, though Adrian was glad Oliver now finally knew. As Adrian was in a board meeting discussing the drug trade Oliver returned though Adrian discreetly taunted him about his inability to confront him, asking if he's "been asleep this whole time".
Later Green Arrow confronted Adrian in a parking garage, firing several arrows at his car in a failed attempt to intimidate him, but Adrian was disappointed that Green Arrow wanted to arrest him instead of kill him. However, Green Arrow firmly told him he wasn't going to kill him if only that's what he wanted him to do. Adrian then told Oliver her had Susan hostage but warned him that if he dies or doesn't get back in time, Susan will die of starvation and dehydration, nor was he concerned with the idea of torture as it would have the same results. Powerless Green Arrow let Adrian go as he pridefully taunted him that he was 10 steps a head of a game Green Arrow still didn't understand and laughed as he left the scene.
Later Adrian ran into Quentin and Rene, also now aware, and told them he liked it better with them knowing who he is now. While they promised to kill him Adrian taunted them by reminding that threatening a city official was a felony and that he was only getting started with his plans, and reminded them to get back to work leaving them powerless to do anything. Anticipating that Oliver would try to use Doris as leverage Adrian tipped the ESU and they arrived in time to confront Green Arrow, and stopped him from getting near Doris. Adrian later attended a press conference to inform the public of Green Arrow's "attempted kidnapping" of Doris as retaliation for his recent "crimes". Because of this Oliver was forced to publicly order Green Arrow to be brought in within 24 hours, or the S.C.P.D. would hunt him down. However this was also a discreet threat to Adrian himself.
After somehow learning that Oliver gave information on his original identity to Captain Pike, Adrian approached him disguised as a homeless man and stabbed him putting him in a coma. Adrian visited Pike in hospital as Oliver arrived who promised that he would kill Adrian as soon as Susan was found. Adrian wasn't threatened by his words and reminded Oliver that if he died Susan would be dead too, as much as Moira, Tommy, Shado and Laurel are, and taunted him that one more loss may just destroy him but taunted Oliver that if he killed him, then he'd only really be killing himself and losing any sanity he has left.
After Team Arrow finally located Susan's location Prometheus was waiting for Green Arrow and he unmasked and noted that he was glad that knew as he preferred it face to face. While Green Arrow threatened to keep them inside until the entire building exploded Adrian deactivated the bombs. However Adrian was caught off guard when Spartan arrived with Doris and exposed his identity to her, proving Adrian really is not ten steps ahead. Despite her attempts to reason with him Adrian told her he loved her but stabbed her in the chest to protect his secret and Green Arrow attacked him in rage and the two proceed to fight. After a heated battle that ended in a draw Adrian told Green Arrow neither would kill the other. Oliver said he could kill Chase but before he could even try, Talia injected him with a tranquilizer arrow and the two kidnapped Green Arrow, taking him to an unknown location.
Adrian later returned to the precinct as Quentin was escorting Susan in for a statement, giving his "sympathies" for her as Quentin threatened him again. However Adrian asked him not to threaten him as he was in mourning, as Green Arrow "killed" Doris, though Quentin and Susan swiftly saw through his lies. However Adrian also reminded them he had Oliver and threatened Quentin and Susan that if they tried anything, he'd send Oliver back to them in pieces. While Susan did still give a statement to the police Adrian had an airtight alibi so they didn't believe her and Adrian's cover remained intact.
In Oliver's holding cell Adrian watched Oliver futility trying to reason with Talia who then told Adrian to make him suffer, which he happily agreed to. As Oliver promised Adrian his friends would find him but Adrian simply reminded Oliver yet again that he wasn't going to kill him. He then told Oliver that he'd confessed to Susan while in captivity that Oliver had helped him discover who he truly was, and promised to help do the same for him before subjecting him to torture.
Torturing Oliver and exposure to the public
Adrian held Oliver captive and tortured him, trying to make him confess what Adrian believed to be the real reason for his killings: that he did it simply because he wanted to, using his father's wishes as justification. However Oliver didn't know what Adrian wanted and Adrian tortured him for 6 days trying to get the answer. On the 6th day Adrian held him underwater for 140 seconds, the same amount of time it took for Adrian's father to drown. When Oliver didn't "confess", Adrian resumed the torture. When Oliver regained consciousness Adrian planted photos of Oliver's victims, but as Oliver reminded Adrian they all had victims themselves, Adrian further pointed out they also had families and they all suffered because of him. He also reminded him of a memorable victim, Count Vertigo, who Oliver had killed to save Felicity 3 years ago, and he let Oliver know the Count's true name.
When Oliver still didn't know what to "confess", Adrian fired three arrows into him, just like he had done to Count Vertigo 3 years prior. After pulling out the arrows, Adrian showed Oliver a pair of Felicity's glasses, having sneaked into her apartment without her knowing, to taunt him. He then showed him a picture of his son, William, and while Adrian admitted that he didn't know where William was, he promised Oliver that he would find him eventually, unless he "confessed". Afterwards, Adrian returned with Evelyn to deceive Oliver by pitting them against each other, promising to let the survivor go or he'd break Evelyn's neck, before leaving to tend to other business. When he returned he was disappointed to see that Oliver hadn't even tried, and Adrian pretended to break Evelyn's neck as she acted dead to horrify Oliver.
Returning, Adrian intensely taunted Oliver, telling him of his belief that everything: the List, the Hood and his heroic crusade; were all just an excuse for why he truly killed. Finally, Oliver cracked, angrily admitting that he had in fact killed because he liked it. Pleased, Adrian mused that he'd made him confess the one secret he wouldn't even admit to himself, as Evelyn dropped her facade and agreed with him. Adrian told Oliver that he was right, that he infected every life he touched as his crusade was based on a lie, resulting in a price, namely the death of his loved ones, and that the still-living John and Felicity would eventually pay it too.
As a reminder of the six days of torture, Adrian took a blowtorch to Oliver's chest to burn away his Bratva tattoo. Before doing so Adrian reflected that Oliver must have done something extraordinary to have earned a captain rank in the Bratva, and how the burned tattoo would now serve as a reminder of his confession. As Oliver tearfully tried to apologize, Adrian accepted the apology but informed Oliver he simply didn't care and burnt away the tattoo, causing Oliver to pass out from the pain. Adrian then left while Oliver was passed out and left his uniform and equipment behind for him, leaving the door open for him as promised.
The next day Adrian visited Oliver in his office, thanking him for "granting him leave" to mourn for Doris' death while Quentin angrily threatened him. When both were alone Adrian gave Oliver a knife and presented an ultimatum; to either kill him as Oliver Queen in broad daylight, as he couldn't reach him as Green Arrow now that he was in protective custody since Green Arrow "murdered" Doris, or let him go knowing there is nothing he can do. Ultimately Oliver declined Adrian's offer, much to his disappointment, and told him to keep the knife as he left. Later Adrian's protective custody escort was attacked by Bratva agents hired by Oliver previously but Team Arrow intervened and Adrian used this chance to escape. While he was briefly confronted by Curtis he swiftly overpowered him, tauntingly asking how Paul was, before Curtis was forced to flee.
In light of the Bratva attack S.C.P.D. decided to transport Adrian into F.B.I. custody and asked Oliver for his approval. Unable to decline without arousing suspicion Oliver agreed and told Adrian, despite his insistence otherwise, that nothing was more important to him than his safety. Before Adrian was transferred he quietly expressed amusement at what Oliver did but Oliver quietly promised that they weren't done and Adrian was transported into custody of the US Marshals. Later as Adrian was writing while in protective custody, he heard his bodyguards receive a message and somehow immediately deduced he'd been exposed. He swiftly threw his pen into one guard's eye before strangling the other to death. Adrian then repeatedly stabbed the first guard to death viciously, strangled the second guard until his neck bled, and left the safe-house. As Adrian was driving down the street, watching the convoy of S.C.P.D. officers going to arrest him drive right past him, he whistled to the radio as he made his way back to Star City, still splattered with blood.
As a civilian
Adrian has appeared to be a kind, caring, selfless, moral individual. He takes his job as a district attorney very seriously, though does have a tendency to lose his temper and is willing to use more extreme methods at achieving justice. After Oliver refused to throw him under the bus for political reasons, Adrian stated that Oliver is not just his boss, but also his friend. However, this was a façade to hide his true motives, as he holds a grudge against Oliver Queen for killing his father, Justin Claybourne in cold blood. Despite his true feelings, he still put on his façade even when Oliver and his team realized his identity as a smug way of mocking them for their inability to stop him despite knowing who he is. 
As Prometheus, Adrian is cold, cruel, sadistic, ruthless, unstable, and has an extreme hatred for Oliver Queen for killing his father in cold blood to the point of vengeance against the latter. Adrian's fixation on Oliver runs so deep that he will threaten and even kill those who threaten Oliver's life, as he wishes to destroy Oliver himself, as seen with Tobias Church when he made an attempt on Oliver's life. Adrian's methods against Oliver are ruthless, merciless, and psychologically personal as he willingly kills innocent people simply because their names are anagrams on Oliver's list, using his victims to recreate the scene in which Oliver killed Justin Claybourne, setting Oliver up to kill Billy Malone who was his ex-fiancée's current boyfriend, and freeing Black Siren to torment him because she is the doppelgänger of Laurel Lance whom Oliver loved. Adrian's end goal is unclear, however, he has stated to Evelyn Sharp that he wants to make Oliver wish he was dead, and prove to him that everything that he touches dies. This also make Adrian a hypocrite as he calls Oliver a killer, despite being a killer himself.
- Master archer: Like Oliver, Adrian is a trained archer although his exact level is unknown due to his preference for throwing weapons. However, he is skilled enough to shoot arrows to either wound or kill his targets, uses it as a improvised quarter-staff like Oliver, and while torturing Oliver he was able to fire three arrow in Oliver's chest in a tight pattern at close range.
- Expert swordsman: Adrian is trained in the art of swordsmanship, often using his sword fighting skills in conjunction with his melee skills; his exact level as a swordsman is unknown.
- Free-running/Acrobatics: Adrian is able to move and scale down walls with great dexterity and grace, even while throwing his shurikens.
- Indomitable will/High pain tolerance: Adrian has a high tolerance to pain as he barely flinched after being shot in the shoulder with a bullet and was still able to move his arm normally even when the wound reopened.
- Intimidation: Adrian possesses an intimidating presences due to his ruthlessness with Tobias Church, Evelyn Sharp, and even Black Siren, a meta-human, showing signs of fear towards him; his killings as the "Throwing Star Killer" combined with media rumors and his presence was enough to cause a city wide panic.
- Master interrogator/torturer: Adrian was shown to be skilled in various torture techniques, both physical and psychological, which he used to emotionally break Oliver Queen. He skilled enough to not kill Oliver despite water-boarding, beating and even shooting him with arrows. However, he was able to truly harm Oliver psychologically by forcing Oliver to acknowledge his helpless state when threatening his allies and even his son, William, and then watch him seemingly kill Evelyn Sharp after Oliver refused to do it himself which in turn briefly convinced him to finish his vigilante career.
- Master hand-to-hand combatant/Martial artist: Adrian, like Oliver, is an incredible martial artist with his fighting style being similar to Oliver's. Adrian was able to effortlessly defeat Evelyn Sharp and Curtis Holt, and was able to fight on par with Oliver during three of their confrontations.
- Master marksman/Knife-thrower: Adrian is an incredibly skilled marksman who is highly proficient in throwing weapons such as knives, battle axes, flechettes and his weapon of choice; shuriken. He was able to disarm police Lieutenant Conahan while jumping and was able to perfectly split an arrow shot at him by Oliver in half by throwing a shuriken.
- Master tactician/Manipulator/Expert detective: Adrian has proven himself to be a highly skilled investigator, having learned much about Oliver and all who are close to him. He knows of their secret identities, the list, the S.T.A.R. Labs pipeline, the multiverse and the Legends. Adrian is also a highly effective tactician, with his tactics against Oliver being at a psychological level, as he was able to successfully trick Oliver into killing detective Billy Malone knowing that Oliver came after Prometheus with the intent to kill him. Adrian is also very manipulative, able to turn Evelyn against Oliver and her fellow Team Arrow members. He also successfully broke Oliver as his methods were so effective that Oliver almost returned to his killer side until he was snapped out of it by John.
- Peak of human physical condition: Adrian is in top physical form after training for four years to defeat Oliver. He is strong enough to pin down the large and physically imposing Church, and Earth Two Laurel, a meta-human, with one arm and kick Oliver through a wooden wall with one leg. He also has a high tolerance to drugs, as he was able to quickly shrug off the effect of the Diazepam-ridden dart that Oliver threw at him. He also withstood a severe beat down from Oliver which left his face bloody and swollen, and barely seemed fazed by it.
- Skilled computer hacker: Adrian has demonstrated some degree of computer skills, as he has used a theatrical trick during his first confrontation with Oliver and Oliver has mentioned that Adrian has erased almost all traces of his identity as Simon Morrison from the internet.
- Skilled metalsmith: Adrian has stolen several of Oliver's arrows that Oliver has left behind during his vigilante career and melted them down to be reforged as his own weapons; mainly his shuriken.
- Stealth: Adrian is highly skilled in the art of stealth, as he is able to sneak in or appear to people fairly quickly without them noticing. He was able to sneak into S.T.A.R. Labs without triggering any alarms, an act that went unknown to them for 3 days.
- Prometheus suit: Adrian wears a protective suit as Prometheus, to hide his identity from his victims, in his quest of vengeance against Oliver Queen.
- Shurikens: Adrian carries Shurikens strapped to his abdomen, usually no more than six at a time. These appear to be his preferred method of killing his victims.
- Quiver: Adrian carries a black arrow container, to carry his arrows with him.
- Katana: Adrian carries a Katana on his back for close quarters combat.
- Axe: Adrian carries at least one axe.
- Throwing knives: Adrian carries several smaller and easily concealable throwing knives.
- Voice filter: Adrian apparently uses a voice filter in his mask to conceal his true identity and making him sound almost unrecognizable as Prometheus. For some reason, he made several alterations to his disguised voice. This is possibly what he used to mimic Lyla Michael's voice to trick John Diggle.
Behind the scenes
- In the DC comics, Adrian Chase is known as the first Vigilante in modern-day, whereas in the series Adrian is a separate character and an antagonist and Vigilante is an anti-villain with a currently unknown identity.
- In DC comics, Prometheus is an alias used by multiple villains, most famously by an unnamed one that pushed Green Arrow past his limits. However, showrunner Marc Guggenheim has stated that the show's version of the character is not based on the Grant Morrison character. Nevertheless, this version does resemble said character in looks and modus operandi, being a mass-murdering "dark mirror version" of the hero he opposes, skilled with several fighting styles and weapons. Another resemblance is that Prometheus' main motivation is to avenge the death of his criminal parent and will go to great lengths to do it, similar to the comics, where his parents were criminals killed by cops and because of it, he wants to destroy all forms of justice. Both claimed to be too smart for Green Arrow to overcome, but were subsequently proven wrong by Oliver.
- He also has similarities to the Batman character Arkham Knight, an alias used by Jason Todd, the second Robin, in Rocksteady's Batman: Arkham Knight video game. Wrongly believing Batman abandoned him after Joker faked his death and tortured him for over a year, Jason swore revenge and adopted darker version of Batman's suit armed with more weapons, with the Arkham Knight alias to kill his former mentor. Adrian suffered a loss at Oliver's hands and uses a darker version of Oliver's suit with even more weapons than he carries as part of his vendetta against him.
- He also has similarities to Hunter Zolomon/Zoom. Both of them are the darker version of their respective enemies with similar backgrounds caused by the actions of their fathers. Black Siren worked with both of them, and both of them help their respective enemies while feigning friendships with them under fake names, and simultaneously opposing them in their evil personas.
- Interestingly enough, his alias mirrors him being the darker version of Oliver, since Adrian literally meaning "the dark one".
- The name 'Simon Morrison' is a reference to the original creator, Grant Morrison, with Simon being based off 'Simon Hurt', a Batman villain he created. The character Simon Hurt also shares many similarities with the show's Simon Morrison.
- Adrian is also one of the three main Arrow antagonists alongside Malcolm Merlyn and Slade Wilson to be credited as a main character and also have past history with Oliver. Additionally he was also the first main antagonist to be credited as a main character in his first appearance in the series.