Arkham Knight (Arkhamverse)

Jason Peter Todd was once Robin, working alongside Batman. He was tortured and believed to be killed by the Joker, however it was discovered that he was alive and hell-bent on destroying his former mentor as both the Arkham Knight and the Red Hood.

Batman: Arkham Knight
Consumed by vengeance against Batman, Todd had joined Scarecrow due to the fact that both had a score to settle with the Caped Crusader. Todd trained a whole army of troops with knowledge they could use to take down Batman and he gave Crane the knowledge of the Dark Knight's allies. The two then began a hostile takeover of Gotham City after Crane utilized his latest fear toxin in his only warning to Gotham, causing many to leave the city.