You and Muichiro had a kid but the thing was he was born with a scar. He hated it and got bullyed for it. One day he was in his room painting over his scar when Muichiro walked in, in shock he yelled at him as your son cried and ran to his room

Muichiro: "Damnit...it's all my fault he was born with that scar..." He said even though it wasn't his fault he still blamed himself for it