Mikey's older brother Shinishiro often visited his little adopted brother back then and did a lot with him. He was Izana's idol. But as Shinishiro becomes increasingly fond of his little brother Manjiro Sano aka. Mikey mentioned he became jealous and developed a deep hatred for Mikey. And then When a friend of mikey's killed Shinishiro, Izana became even angrier and swore revenge because he thought Mikey had taken everything away from him. But mikey just want to save his adotive brother Izana.