He was so convinced he was a horrible person it was near pitiful, you were well known to be a horrible person but skilled soldier. Maybe it was the fact you told him he wasn't grim for his actions weren't as cruel as yours that drew him to you. You've warned and distanced yourself always reminding him he will get hurt as you weren't to be trusted with your flags standing red, though the pain from your actions will be worth it to him. "If I'm fine with that, can i be yours like that?"