'''Basic Trope''': Antagonist [[TheReveal turns out to be]] a former friend of one of the good guys.
* '''Straight''': Noien, a MagnificentBastard who's been bothering the heroes for some time, reveals his identity -- Noien is actually Noel, Carol's childhood friend!
* '''Exaggerated''': Noien is Noel! Carol's old BFF who mysteriously vanished from her life without a trace! And they had a ChildhoodMarriagePromise together!
* '''Downplayed''':
** Noel was just a classmate of Carol's in school. They didn't really know each other that well and he was always kind of a {{jerkass}} anyway.
** Noel is [[UndercoverCopReveal an undercover agent]] working for the [=FBI/CIA/equivalent=], though there's still heavy JurisdictionFriction between his group and Carol's.
* '''Justified''':
** Carol is suffering LaserGuidedAmnesia.
** Noel was very meek and unnoticed, but Carol, being the nice girl she was, hung out with him because she didn't like seeing him alone. She forgot about him because she had too many other friends at the time, and can't really remember any of her friends from childhood that didn't grow up with her.
** Noel made sure that he was forgettable as a child, even if he didn't know what he was going to do in the future.
* '''Inverted''': Carol's new BFF is revealed to be the AlphaBitch who picked on her in grade school.
* '''Subverted''': Carol believes that Noien is in fact Noel when he talks about their shared childhood. But it turns out that Noien is in fact a stalker who's been following her since her birth.
* '''Double Subverted''': ...But then it turns out said stalker really 'is' Noel.
* '''Parodied''': Noien is revealed to be... somebody Carol walked by once who fell in LoveAtFirstSight and is ''mortified'' when she doesn't remember him.
* '''Zig Zagged''': DependingOnTheWriter, Carol behaves as if she kept in touch with Noel all along or didn't.
* '''Averted''': Carol has never seen Noien in her entire life, nor he, her.
* '''Enforced''': "Carol needs an emotional moment here. I know! We'll reveal that the BigBad and her have history together. The audience will eat that up!"
* '''Lampshaded''': "Wow, you've changed... You're taller, you're not six years old any more... Oh, and last time I saw you, you weren't evil. Love what you've done with your hair, by the way."
* '''Invoked''': Emperor Evulz tracked down Noel and deliberately turned him against Carol and her friends as a weapon.
* '''Exploited''': ???
* '''Defied''': Despite apparently being forgotten, the friend remains loyal.
* '''Discussed''': ???
* '''Conversed''': ???
* '''Deconstructed''': The story goes into some detail about the kind of person who would utterly forget their friends. Carol was so obsessed with answering the Call that she gradually started ignoring poor Noel entirely, causing their friendship to end and her to forget him. Carol looks rather callous and unheroic when the reveal happens as a result.
* '''Reconstructed''': Carol has made many friends on her adventures, and besides, Noel drifted away largely on his own.
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Back to ForgottenFriendNewFoe.
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%% Optional items, added after Conversed, at your discretion:
%%
%%* '''Implied''': ???
%%* '''Plotted A Good Waste''': ???
%%* '''Played For Laughs''': ???
%%* '''Played For Drama''': ???