Since day one they were always hand in hand, playing, jumping and laughing. Their mother's, Rei and Tomie were also friends since childhood but the only difference was they grew up together. Their children on the other hand didn't.
Keigo, Tomie's son and Touya, Rei's son. Shortly after Tomie had Keigo, Rei had an arranged marriage to Enji Todoroki who was soon to be 2nd pro hero. 3 years later they had Touya which Enji was desperate to train him to become number 1 hero, to be better than him. Fortunately for him, Touya had fire power like his father but even poor Rei didn't know marrying Enji would leave such a big impact on young Touya's life.