Nimdok

Nimdok is one of the five main characters in I Have No Mouth And I Must Scream. He is one of the last five humans on Earth and has been tortured by AM for 109 years along with the other four. In the original story, his dark past is only alluded to, as he is known to wander away from the others for long times and come back visibly shaken. His story is elaborated on in the game.

In said game, it is revealed that Nimdok was the right hand man of Josef Mengele at Auschwitz who performed similarly horrific operations on hundreds of Jews. Moreover, Nimdok was a jew himself, and sold out his family to the Nazis and agreed to work with them in order to escape being killed himself. Like Mengele, Nimdok survived the war and went into hiding until AM came to power and chose him as one of his torture subjects since he probably deserved it most out of all living people and thus would be more fun to torment than the average person.

The scenario AM puts Nimdok in as part of his "game" is a direct recreation of Auschwitz and the people there in 1945 near the end of the war. The correct path while playing as him involves betraying the other Nazi scientists and freeing the jewish prisoners. However, they cannot forgive him for what he has done and only give him a head start before chasing after him. Nimdok escapes to a nearby bunker where a golem that was stolen from the jews in order to destroy their morale is being kept, as well as a magical mirror created by the Nazis that shows anyone who looks into it the objective nature of their soul. Dr. Mengele follows him here, and reveals that the reason Hitler killed himself is because he looked into this mirror and saw how evil he really was. Nimdok can make Mengele look into this mirror, and what he sees is so horrifying that he goes so catatonic that he doesn't even fall over. Nimdok then brings the golem outside where he is confronted by the jews. He then must either have the golem turn on the jews and destroy them (bad), or give control of it to them and let it kill him (good). Note that he doesn't actually die, since the entire thing was only a simulation created by AM.

Nimdok has the distinction of being one of the most evil villains in any story to ever even try to change his ways. In other words, he genuinely repents and tries to redeem himself even though he'd long since crossed the Moral Event Horizon. It is impossible to get the good ending with him, since he is truly irredeemable. The closest he can get to redemption is to help another defeat AM and revive the human race through the lunar colony, dying in the process. The in–game narration after this happens confirms that Nimdok went to Hell like even he knew he deserved.

Nimdok is also an example of the trope known as "Heel–Face Door Slam" in which a villain attempts to switch sides after it has become too late for them.