Dark Ericho was created by the virus fragment that Ericho took away from Raccoon in episode 048 - "Fragmented Death". The fragment escaped from Ericho's body when Kageto, Kagemamaru's "son", appeared and that's how Ericho got killed. After defeating Torben on their mission at the Dungeon Space in episode 054 - "Virus Fragments pt.II", the heroes went in to the vault, and there they found Dark Ericho himself hiding inside of a virus frag that alpha was about to destroy with the anti-virus program. Flamegirl went to see if its the real Ericho she knew, but it wasn't, then they began a fight. Flamegirl won the battle with a triple fire attack. Then, instead of destroying it, Alpha took the fragment for himself and used it against Voltarios. When alpha and Zetto saved Kirbopher from the D-bug in episode 60.5 - "Duel Of The Dragon (part 2)", Ericho came back to life in Purplecave.