User blog comment:ZSomji16/The Flash (Season 4), Arrow (Season 6), Legends (Season 3), and Supergirl (Season 3) Villains and Big bads/@comment-24152851-20170327122115/@comment-27700324-20170327153924

Trigon wouldn't work. He is way too powerful and at least Deathstroke actually fought Oliver in comics. Damien was the one time that it wasn't a Green Arrow foe.