Ebonite

Mister  was an alien technology trader. He abducted Jack Harkness, Cindy Wu and Cleo. The Monaxi, his servants, activated a time bridge and brought the Tenth Doctor and his crew to the Arena of Fear as well. After Ebonite states that "anybody could be their enemies", Tony, Gabby and Unta can be seen under his control inside the Arena of Fear.