In the comics, Jason Todd was the second Robin. Originally a circus artist whose parents were killed by Killer Croc, after the Crisis on Infinite Earths, this was changed to be less like Dick Grayson's origin. He was recreated as a street orphan who tried to steal the tires of the Batmobile.
Jason was killed by the Joker in the highly publicized A Death in the Family event. He was revived when Superboy-Prime changed the multiverse in Infinite Crisis, and has taken the persona Red Hood since then. He continues to fight criminals, but in a more brutal manner, not shying away from torture and murder.
This is Jason's fourth animated appearance. He first appeared in Batman: Under the Red Hood, and his image had a cameo in Teen Titans, the New Teen Titans shorts, and Bat-Mite showed his death scene in Batman: The Brave and the Bold.