Do tell more.
Alright, guys, this'll be kinda long.
In the third book for my main series, one of the mcs is possessed by the main villian, Sycore. (the reason why is really complex because this is me writing this series XD) Halfway through the possession period, the MC, Tom, is so deep in Sycore's head that he can see his memories and his backstory.
Basically, Sycore's like 8-13,000 years old. He had a girlfriend before he was trapped in a relic.
Her name is Hicia. She was a provincial heir, rich, intelligent and posh. Sycore was a child forged by neglect, abuse, and the coldness of life. By fate they met and fell in love.
And when Sy gained power over her, he manipulated her. It started small, but when he gained possession of the relic that trapped him, an amulet that gives the user powers in exchange for their soul when they pass, it got progressively worse.
He became a raider of their village and the surrounding ones. He killed people for the pure euphoria of it. Yada yada, fantasy horror things.
She begged him to stop and gained possession of the second amulet. (there are three because my world is… complex as fuck) He tortured her and killed her, but not before she gave him a fight, enough to make him die of severe blood loss after.
It's excessive, but it's supposed to be an eye opener to the signs of emotional and mental abuse. That if they use you, run.