He is Koji Minamoto's twin brother. Their parents divorced when they were very young, so they hardly knew about each other. Koichi learned about Koji when his grandmother told him on her deathbed. He ran after Koji, who was on his way to the Digital World, to try and catch up with him but he fell down a flight of stairs and ended up in a coma as a result. His mind was taken into the Digital World by Cherubimon, who saw his sadness.
