Yu had a big rift between him and his son, Koji, who was in the middle of puberty. Their relationship was a bloody and serious one where they cursed each other when they met face to face. "I'm not good at studying, I'm not good at exercise, and I'm not considerate. I'm sure I'm not popular with girls. I really wonder why I gave birth to such a child." Koji, whose anger reaches the peak with this word that Yu released, forgets himself and attacks Yu.
