Kotaro has mid-length green hair with a shorter, darker green undercut and green eyes . He has an intimidating appearance. Though short-tempered and often exuding an intimidating aura, Kotaro actually has a caring and fun personality. True to his image, however, Kotaro has quite an intense disposition, and expresses his enthusiasm by exclaiming loudly. 
he scares his juniors, but is very respectful to his seniors. He acknowledges his errors and always profusely apologizes to them.