Udono is Gennosuke's portly and jovial best friend. Altough he is very friendly, he faces massive rejection from the ladies. Often coming across as abrasive, he speaks his mind, and is unabashedly honest.

Udono's redeeming quality is his ability to expand and contract like a balloon. Because of his rubbery nature, weapons bounce right off of him. But unfortunately for Udono his trusting nature opens him to sneakier, underhanded attacks, which could ultimately lead to his doom.