- Magic: The Gathering:
- Crovax and Ertai of the Weatherlight crew turned in two completely different ways. Crovax did so through a vampiric curse triggered through his own slaying of his Guardian Angel, Selenia, and completed the turn by killing Mirri and assuming the Rathi evincar-ship in Volrath's absence. Ertai, meanwhile, was systematically broken during the Nemesis storyline, going fully under Crovax's sway on the realization that his crewmates had abandoned him to his fate.
- Urza dedicated himself to fighting against the forces of Phyrexia and spent millennia taking steps to defeat them. Once he actually found himself in Phyrexia however, the Mad Scientist in him couldn't help but admire the sheer genius of its design. He eventually turned on his fellow planeswalkers and pledged himself to Yawgmoth because he couldn't bear to destroy a plane that embodied everything he had sought.
- Betrayal at House on the Hill has this as its main mechanic: the players start out exploring the haunted mansion together, but once the Haunt is triggered, one of them turns Traitor and tries to complete their evil mission before the others can stop them or escape.
- Warhammer 40,000: A major part of the backstory is Horus's fall to Chaos, which tears the Imperium of Mankind apart. A rather more minor part of the backstory is the FaceHeel Turn of the Eldar Phoenix Lord Arhra. With The Corruption a constant threat in the game universe, Face-Heel Turns are a constant threat to all the greyer factions.
- Chaos is made up mostly of deserters from the main protagonist faction, the Imperium of Man (almost everyone in the forces of Chaos is either an ex-Imperial or a daemon); that treachery began when The Paragon Horus betrayed the God-Emperor of Mankind.
- The Dark Eldar are the result of a whole civilisation, the ancient Eldar empire, turning into evil hedonists full of crime-loving "pleasure cults", and accidentally creating a dark god; the Craftworld Eldar turned their back on it became good guys (well, comparatively good, anyway) but the Dark Eldar went on with the whole pleasure-cult stuff and they're now the most evil faction in the setting. The Dark Eldar Incubi (who are essentially a dark reflection of Eldar Aspect Warriors who follow Arhra's teachings) have a slightly different take on Arhra's FaceHeel Turn: both versions of the story agree that he was corrupted by the forces of Chaos, but in their version he soul remained uncorrupted, at least long enough for him to order his disciples to fight and slay him. The Incubi are still evil though, but unlike other Dark Eldar they at least follow a strict if merciless code of honor.
- Asmodeus and most of his archdevils used to be members of the forces of Heaven, before a rather pointed disagreement on the concept of free will led to them either marching out of Heaven or getting kicked out (accounts differ depending on who's telling the story) and winding up in Hell. The Queens of the Night Eiseth, Ardad Lili and Doloras likewise used to be angels before becoming devils — Ardad Lili left during the devils' original exodus, Eiseth fell after murdering her commander and Doloras found she was no longer welcome in Heaven after a throughly unnecessarily sadistic campaign against demons.
- Zon-Kuthon, the god of sadism and torture, used to be a kind and benevolent deity named Dou-Bral. This lasted until he went exploring beyond the reaches of the multiverse, where he met... something that changed him into the monster he is now.
- There are rumors that Nocticula, the demon lord of lust, succubi and assassins, used to be a powerful celestial being who fell and fell hard.
- Dungeons & Dragons:
- The worst kind of Blackguard, and by far the most powerful and feared, is one who was once a paladin. A fallen paladin who becomes a Blackguard gains extra abilities, and the more levels of paladin they had, the more powerful they become as Blackguards, and if a particularly high-level paladin goes bad this way, he or she can trade in ten levels of their former paladin class to become a fully-powered Blackguard with all abilities, as well as extra abilities based on how many levels of paladin they have left after the FaceHeel Turn.
- Asmodeus is generally recognized as having started as a force for good before becoming He Who Fights Monsters, appropriate considering he's the single straightest analogue for Satan in D&D. On the other hand, having a Multiple-Choice Past and all, a few origin stories state that not only was he always evil, he is in fact one of the original, primal forces of evil from the beginning of the universe.
- The Archmage Rary became known as "Rary the Traitor" after he tried to kill the Circle of Eight at the signing of the Treaty of Greyhawk after judging them to be too quarrelsome to be effective in their goals. This led to the deaths of Tenser and Otiluke and Rary having to flee to the Bright Desert with his co-conspirator Robilar.
- In 5th Edition, there's a special class called "Oathbreaker" that serves to reflect a Paladin who has broken their sacred oath.
- A Touch of Evil: Whenever you select a Town Elder who has an Evil Secret for your Hunting Party.
Face Heel Turn / Tabletop Games