The Dark History Of DC's Robin

In D.C.'s "Injustice" universe, Robin kills himself. Well, sort of. For context, the "Injustice" universe details an incredibly dark timeline in which the entire cast of characters loses the best versions of themselves. It encompasses the events of the "Injustice: Gods Among Us" video game and prequel comic series, beginning with the Joker's efforts to possess members of the Justice Society with an evil amulet and using this power to cause great harm to the heroes.

In this darker universe, Damian Wayne, in an outburst, accidentally kills Dick Grayson. Damian, as petulant and self-important as ever, takes out his vindictiveness on the Riddler, beating him while he's on the ground until Dick Grayson, as Nightwing, reminds him that Robin doesn't beat people while they're down. Damian basically has an immature "You're not the boss of me" reaction and throws one of his batons at Dick. Caught off-guard, Dick stumbles back and falls, breaking his neck on a rock as he hits the ground. 

Once again, Damian's ridiculous personality creates a terrible situation. Both of these characters eventually don the mantle of Robin at various points in various timelines, so one (much less likeable) version of Robin technically kills another! The boy who comes to play a newer version of Robin kills the one who donned the mantle originally.