Grindelwald may have been Dumbledore's former BFF/secret lover, but it's still hard to overlook the fact that he was basically the wizarding world's Hitler. By the time he dies, he's minding his own business, serving a life sentence in a dingy old prison, when Voldemort comes calling. And he doesn't leave loose ends. He Who Must Not Be Named is looking for the Elder Wand, and is predictably none too pleased when Grindelwald is the opposite of helpful. So just like that, Grindelwald meets his maker, and the man whose notoriety is only lessened because Voldemort exists is dead.