Despite being considered simple minded, it is shown he has reasonable observation skills and shows some common sense when not thinking about fights and food, at one point noticing Jyugo's skills with puzzles and wondering why he can't put it to better use. He is also shown to be capable of following orders when he desires, despite normally not liking authority, as he was the only one of his inmates to be able to build a competent drawer unlike Uno, Jyugo, and Nico, who got distracted and made their own wooden sculptures or contraptions out of the drawers. He is rather loud and impulsive but when given food he calms down. His love of food is stronger than his love of fights, as Hajime is usually able to calm Rock down by giving him a menu for the prison lunch, causing Rock to sit quietly staring at it and drooling. In addition, he compliments the assistant Chef Shiro's food quite often. He is also shown to have a fondness for women (though to a far lesser extent than Uno who is more perverted and has more experience), staring and blushing when he sees a beautiful woman but doesn't actively flirt with them.