Hoff [Polymock Master], who can be found in Rata Sum is the quest giver for the Polymock line of quests. He will give you your first three Polymock pieces when you speak to him for the first time, enabling you to play Polymock.
You somehow deafeated me playing by commoner rules. I'll give you that. Now let us play by tournament rules. I cannot be defeated! You'll need 1 common piece, 1 uncommon piece, and 1 rare piece to play.