Biden, from Ultima Underworld
Some time before the Avatar arrived on the level, Dorna Ironfist sent Biden to deal with the chaos knight Rodrick. However, Rodrick soundly defeated him, forcing him to retreat, and the Avatar met him in Ultima Underworld I on his way back to the stronghold. Biden told the Avatar of the battle, how Rodrick had shugged off blows that should've been lethal, and warned that he was a horrible enemy to deal with.
Later, he was rescued by Garamon when the volcano erupted.