Running through my list of prospective candidates:

• Hiyoko-kun, a massively OPed baby chicken for its size who may or may not have learned from both Bruce Lee and Chuck Norris, and would probably be a multi-class... nah, doesn't really fit here, especially with what will probably be a large amount of luck being involved.
• a capitalist Chocobo who really loves rolling dice and running shops, and would probably be a thief... cute, but this is Dadotoci, not Monopoly. I'll pass.
• Setzer Gabbiani. Wears heavy armor like a warrior, but uses dice and cards as weapons... perfect!

_{A sprite of Setzer from Final Fantasy 6, so credit goes to Square Enix.}

Setzer Gabbiani... the higher he rolls, the harder he throws! (And the more damage he inflicts on enemies.) He enters IBT#3 as a warrior.