How Come All the Magical Girls We Promised Have Turned into Yanderes?

A few years ago, the devil came and the world was in crisis. In times of despair, countless girls awakened as magical girls, and Gu Chen awakened as a "familiar", responsible for assisting the girls in the contract to fight bravely. In the final battle of the demons, in order to block the fatal blow for the girls, Gu Chen sacrificed himself and died with a smile amidst their heart-rending cries. When he opened his eyes again, he found that he had been resurrected by the magical girls he had contracted with in the past. It's just... All those gentle and kind comrades seemed to have gone dark? ! "Gu Chen, just lie in bed obediently for the rest of your life. Don't think about anything, I will handle everything." "Junior, are you willing to believe me? Although everything I do is suspicious, my purpose is to make you the happiest person~" "Magical girl? Witch? Demon god?... I can't remember clearly. It doesn't matter, as long as anyone dares to get close to Gu Chen, I will do it all..."