Tess

Bro. We're talking about mentors, not perpetrators. AFO literally groomed and manipulated Shigaraki. Endeavor was hardly worthy of being called a mentor. Aizawa definitely belongs higher up on the list since he was constantly looking after his students and supporting them, whereas All Might focused solely on Midoriya for the most part. Aizawa is number 1 for me.

Are you for real? Endeavor? He was a narcissist that beat his wife and kids. So, add the children and Rei. Also, where's Aizawa? Like? Helloooo... He's like the one that's a chronically depressed PTSD individual that clearly doesn't take care of himself and had survivor's guilt. But yeah, let's go with Endeavor as one who suffered more.