: A character's mentor or idol becomes loathed by them for evil actions.
- Straight: Bob once taught Chris noble martial arts, and Chris uses his ninja powers to catch Bob committing crimes.
- Exaggerated: Bob, once a pacifist and a lover of kittens, has crossed the Moral Event Horizon and is barely recognised as Chris' original mentor, such is the atrocity of his crimes.
- Downplayed: Chris discovers that his mentor, Bob, has sold out and started churning out useless self-help guides for a quick buck, causing Chris to feel somewhat contemptuous.
- Justified: Bob was forced into a life of crime due to living in a Crapsack World.
- Bob used to train villains to commit crimes, and now does good acts instead.
- Alternately, Chris is the one who starts committing crimes using the training he got from Bob, much to Bob's disgust when he finds out.
- Subverted: Chris has misinterpreted Bob's actions; he is in fact a Good person
- Double Subverted: Then Chris learns about all the downright nasty crimes Bob has committed.
- Parodied: Chris becomes disillusioned with Bob for horrendous crimes against fashion.
- Zig Zagged:
- Bob appears to be committing crimes, but then it turns out he has good intentions behind them, according with his original teachings. Then Chris learns this is just a cover-up to commit horrendous acts - it then transpires someone told him this, and it is a blatant lie.
- Chris catches Bob in a Face Heel Revolving Door.
- Averted: Bob has always been the same noble teacher.
- Enforced: The writers decide Bob needs some Character Development.
- Lampshaded: "You were once the noblest man on Earth, Bob. Now, I can't hold you in the same light I used to. Look at what you've done!"
- Invoked: Bob decides to go under an alias and commit crimes in another city. The city where Chris is now policing.
- Defied: Bob is highly disillusioned by the Crapsack World, but decides keeping his principles is more important, especially with all the people he influenced over his life looking up to him.
- Discussed: "That Bob has started beating up pensioners, raping kittens, and littering - how long before Chris finds him, and loses all faith in him?"
- Conversed: "Chris is going to be so pissed when he finds Bob doing all this stuff."
- Chris spirals into depression over the intense hypocrisy of Bob's good teachings and his current evil actions.
- Alternatively, Chris finally realizes that Bob was always a simple asshole instead of the Knight in Sour Armor he always thought he was; it's just that he (and Bob) have never let himself admit it.
- Chris takes strength from his original teachings, and they allow him to call out his ex-mentor for his descent into villainy.
- Alternatively, Chris realizes that what Bob does doesn't really matter as long as Chris is still a good person.
A true Troper would use the link back to Broken Pedestal
. You taught me that. So...why?