Chase - Arrow: Season Three

A member of The League of Assassins serving under Ra's al Ghul, Chase (d. February 2015) was tasked with assassinating Thea Queen, after the latter - under the influence of Malcolm Merlyn - murdered Sara Lance, Ra's daughter's girlfriend. 

Getting close to his target, he made himself amiable to Thea, working as a DJ at her nightclub, Verdant, after her previous DJ bombed. Refusing to take her money, he instead took a kiss as payment. 

Hoping to start a relationship with Queen, she refused his advances, wanting to keep their relationship strictly professional. 

Chase continued to track both her and Malcolm, feeding intel back to fellow assassin Sarab. 

While Chase was devoted to his mission, he did form a genuine friendship with Thea. They eventually spent a romantic night together. Getting her alone, he laced her wine with cyanide, hoping to give her a quick and painless death. When this failed, thanks to Thea's training under her father, he fought back, attempting to slit her throat with the cheese knife she attacked him with. 

Although he was initially able to hold his own against Thea and Arsenal, who had arrived on the scene, he was overpowered by Merlyn, who shot him in the back. Rather than reveal his master's plans, Chase drank a second vial of cyanide, ending his life.