Fan Fic: Ace of Spades

Ace of Spades by LeontinaStardust available on and Archive of Our Own is a Batman: The Dark Knight and Harry Potter Crossover and Slash Fic (The Joker/Harry Potter, Poison Ivy/Harley Quinn).

After saving the world Harry gets PTSD and loses control of his magic, accidentally killing Ginny Weasley. The Magical World, not wanting to get their hands dirty with charging their world's savior quietly strips Harry of his wand and has him secretly sent to a Muggle Asylum. Forsaken by the very people he saved Harry is shuffled between various mental institutions; none of which are prepared to help a wizard and Harry's condition worsens into full on psychosis. Harry ends up in Arkham where he makes the acquaintence of a mad doctor with a burlap sack over his head that wants to use him in his experiments, a police officer that is actually concerned about his well-being, and a fascinating man with scars on his face who also wants to see the world burn...

(Has nothing to do with the video game of the same name.)

Ace of Spades provides examples of: