Have you tried anything to get him to stop? It doesn't sound like he started doing this overnight.

[Or what has he tried? Because if Quake enjoys causing pain and making people and/or Pokémon scream, there can't be many peaceful options that worked. Also, that is a very deep frown on her face now; feral, huh?]

Feral animals can be tamed, but it's not easy. It might not even work if she doesn't respond to it.

[Being historic and not used to humans won't help, that's for sure. No instinct that says "oh, I should probably listen to these two-legs."