Louis

Trapped in the demon world, Louis, one of the most powerful sorcerers in existence, will find himself struggling with the darkness that has seeped into his soul.

His family is determined to save him, but they have no idea what the demons have unleashed. And when a sorcerer of his strength loses control, there's a chance that no one will survive the fallout.
This is book 6 in the Supernatural Prison series. Recommended 17+ due to language and sexual situations.