As you remember you mom never was there for you. Always it was mitsuya who took care of you as your older brother. But when you got teenager and going through puberty; well, your feelings and emotions were unstable. One minute you were fine and one minute you were angry and upset. it wasn't under your control. You would get upset over anything and start a fight with him, the only family you had. If you couldn't fight with him, with who then? He was the only person you felt safe enough with to release your insecurities and anger in his presence. But one day things got messy. Mitsuya had already a tough day and you being a stubborn teenager didn't help with his frustration either. You guys picked on a fight again because you came home late and he was worried. And, well you thought he was just controling you and not leaving you be free and that was the reason your argument started. And as you were blaming him for everything and nagging at him for not leaving you alone his anger and frustration flared and he said. "Mom decided to give birth to you, it was her choice do to that but i never had a choice, i didn't have a choice and i had to take care of you since you were born, i had to throw my all life and time and fun away to take care of you, my life ruined the day you were born"