Thread:Jester of chaos/@comment-5754292-20160223170035/@comment-26884760-20160223171043

it is detailed as such "remembered for the villains they become", a brainwashed villain can stay if they are known primarily as an antagonist for a good while in their setting, even if they are brainwashed.

Midnight Sparkle failed because she was far more a victim than an antagonist, her villainy pales in comparison to the Headmistress, who was one of the rare Karma Houdinis in MLP canon and an emotional abuser.

Further, it was very brief and MS quickly went back to being "good".. Rita, Zedd and Nightmare Moon had much longer periods of being "evil" and became established antagonists in their realities as a result.

Just like Darth Vader, who was brainwashed by Palpatine, Vader is still a villain because his brainwashing lasted over several movies and he did not truly feel remorse or redeem until near the very end.. thus the name "Vader" is associated far more with evil than good.

Basically if a hero is brainwashed for only a brief moment they don't count, they must remain brainwashed for enough time that they can establish themselves as a vilainous figure (even if they later redeem).

(P.S. Nightmare Moon is technically not just brainwashing, some canons of MLP suggests Nightmare Moon is actually an evil spirit and Luna was simply one of its hosts)