*Yawns*

Or maybe they could make the coliseum like that of Dragon Quest's monster coliseum where you select a retainer, place a bet on them and have them fight in single or teamed combat with other retainers in a turn-based style battle system and have the option to participate in tournaments or selected or random one on one or party versus battles that give you the option of having your retainers fight a certain amount of rounds to determine the winner.