Odischamp is a player spoof involved in The Elder Kiln. He is found fighting in the Fight Pits to kill several Ga'als. He must be defeated during the quest. He attacks mainly with Earth Surge spells. Protect from Magic or Deflect Magic would stop a majority of the damage. Players are strongly recommended to kill him first as he starts off attacking Ga'al-Jeh. He has a fairly high defence, but it shouldn't be too much of a problem for players with 80+ Attack.
It should be noted that he can hit pretty accurately into the 300s, so protection prayers are very useful.
He appears to be wielding an
amulet of glory, an unholy book, an ancient staff, a pair of light mystic gloves and Ahrim's robes.
Odischamp holds his ancient staff like a chaotic longsword or an armadyl battlestaff, just like LolthenKILL's staff of light. It is possibly made like that so players don't get spoofs confused with real players, because you must battle them.
Cow1337killr mentions in Festival of the Dead that Odischamp never liked anything and that he took any update from RuneScape negatively. This could be a reference to the negative feedback Jagex has been receiving from players after an update through their Facebook page, Youtube videos and the RuneScape forums.