Constantine Drakon

Once he started killing people at the age of ten, however, he found he was no longer sensitive about his stature.

Oliver "Green Arrow" Queen's investigations into the monsters put him in direct confrontation with the European assassin.

[3] Drakon's next victim was attorney Joanna Pierce, niece of Black Lightning, who discovered information proving that an imperfect vaccine the Elevast Corporation produced had in fact turned human beings into the troll-like creatures.

[4] Drakon would subsequently invade the Green Arrow household looking for copies of Joanna Pierce's evidence and face Connor Hawke in battle.

Drakon attacked Green Arrow's former sidekick Arsenal, cutting the young hero's throat and taking him prisoner.

[7] Deathstroke the Terminator allowed himself to be caught by Green Arrow so that he could meet with Drakon in prison.

Drakon not killing Green Arrow.