Maybe I should have slept on this question for a little bit, but here I go.
I am working on a TRPG and a setting that would accompany the TRPG. In my setting all monsters are or were humans, so rather than slaying them, as in D&D, you can always "save them" and "turn them back" into humans. Thus, the players will always have a dilemma when meeting a monster - do we risk capturing and saving them or rationalize why it was okay to kill it, punish it?
In order to keep this narrative, I need to populate the setting with monsters that could be "saved" and create traditions (magic, tales, etc.) on how to "save" them. Thus, I am looking for real-life mythologies and folklore that could function as inspiration.
What I am NOT looking for is traditions about werewolves being able to transform into a human. I am talking about the idea that all monsters are or were humans once, and by doing "X" (like helping them, performing a spell, ritual, etc.), the monster can be "saved" and turned back into a human or at least civilized.
I also know that Christian exorcism exists, but is there anything else?
Honestly, any info about similar concepts like "monsters turning back into humans" or "monsters being saved or re-gaining their humanity" would be appreciated. I can read on the specific myths or traditions myself.
Thank you for taking the time to read and answer my question!