Oliver Queen went looking for Alexi, to get help identifying Floyd Lawton by his trademark bullets. At first, Alexi thought him to be an enemy, but Oliver proved his credence by showing him his Bratva tattoo. Alexi agreed to look into the bullets and discover the identity of the user. He warned Oliver, promising that he would have he and his family killed if he was lying about who he was. He later called Oliver to confirm Lawton's identity.
Sometime later, Oliver asked him to arrange a meeting with The Count so that he could buy the drug Vertigo. Alexi revealed that he had learned of Oliver's identity and was surprised that an American had gained such a high rank in the Bratva. He agreed to try to arrange a meeting if Oliver could perform a task for him. He brought in a man, claiming that he did something against his wishes, and asked Oliver to kill him. Oliver used a move Yao Fei Gulong had once used on him, making it appear as if the man was dead. Tricked by the manoeuvre, Alexi arranged the meeting for Oliver and attended it, but a police raid interrupted the deal and Alexi and company fled.
Oliver again asked for Alexi's help, in order to uncover intel on Slade Wilson. As usual, Leonov asked a favor in return, but Oliver refused to comply, taking out and injuring his men in order to persuade Leonov to do this favor. Alexi obliged but informed him that he would no longer be associated with the Bratva, regardless of who his friends were. A short while later, Alexi was killed with an arrow to the eye and was taken to Slade Wilson's office, where he was found by Oliver.
Alexi was a "you scratch my back I scratch yours" type. He did favors for Oliver but expected one in return. He was however, not unreasonable as the first favor he did for Oliver was free since he and his mechanic disrespected Oliver without realizing he was Bratva, moreover, a captain. He didn't like dirtying his hand as he requested Oliver to kill a man before investing into Vertigo. He couldn't compromise for an emergency request and still demanded a favour first.
He knows criminals who sell drugs and their personality type like The Count.