(北大路斎 Kitaōji Itsuki), Seiyū - Kenji Hamada

He has an obsession (that matches Hijikata's obsession for mayonnaise) for putting ketchup onto basically everything he eats, even on top of tomatoes. He claims that he used to hate ketchup so much that it made him puke, but as a form of training, he has forced himself to putting ketchup onto everything he eats to the point that he has fallen in love for it.

His name is based on Satsuki Kitaooji of the manga Strawberry 100%.

Source: Wikipedia