Terra

From Superdickery

Terra was a member of the Teen Titans who joined Deathstroke (Or Slade as he's known as on the TV show for some vague reason) and betrayed the team, in one of the more famous of the storylines of the series.

In the cartoon, Terra became Deathstroke's apprentice, was more empathetic and died a hero's death. In the comics, she was an evil and crazy fucking bitch from the get go, and it is heavily alluded that she and Deathstroke had creepy pedo sex.

Either way, she's dead, even though there's still a Terra in comics that hasn't really been explained by anyone. Oh wait, she died too. Well, now there's another one. She has black hair and also hasn't been explained. She might possibly have a miniseries in the next decade maybe to fix this.