Rorek of Nol from Teen Titans. The only record of his existence was the prison for his mortal enemy, who has proven he can fuck up the contents to whatever he wants. Just think of the possibilities for extreme slander and libel.
Bane from the "Matrix" sequels was pretty screwed. The poor guy risked his life to let his friend escape Agent Smith, and Bane himself wound up possessed by him. His body is then used to murder Bane's own crewmates (and presumably friends), until Neo finally smashes him to death. And afterwards, I don't think anyone is made aware of the fact that it wasn't really Bane doing all those things. The only consolation is that hopefully Bane's consciousness was erased the minute Smith possessed him, so at least he didn't have to experience all of that.