Guillermo Barrera (died March 2013) was a mercenary who mostly operated abroad.
Guillermo Barrera was hired by China White to kill Malcolm Merlyn, under the order of Moira Queen. The moment he arrived in Starling City's airport with his helicopter, he was confronted by The Hood, and after a brief fight, was killed. After hacking his phone, Felicity Smoak identified his target.
- Expert combatant/Martial artist: Barrera showed to be quite a good fighter. His fighting skills were enough to contend with The Hood for a short while. During the fight he was able to easily cut down arrows shot at him.
- Peak of human physical condition: Barrera was in top physical condition as a mercenary. He could deflect arrows shot at him.
- Knives: Barrera carried a pair of knives which he used to fight against his opponents up close.
- Throwing knives: Barrera carried a number of throwing knives which he used as a means of attacking from range.
Behind the scenes
- In DC comics, Guillermo Barrera is the super villain Brutale, a recurring enemy of Nightwing. Also, in the companion book named Arrow - Oliver Queen's Dossier (released in September 2016), it is mentioned that he was enemies with Nightwing, although, the latter one didn't appear in the show.