Kotaro is an effeminate young boy, even going so far as to refer to himself as "delicate", and is the strongest member of the blue clan. Because of this power he could not control, he spent most of his life locked away in his room, and for four years prior to the start of PAPUWA, was in a coma. He has the bearing of a spoiled, pampered child, and believes he is above everyone. Somewhere between waking from his coma and arriving on the island, he became amnesiac. Liquid, fearing that remembering his own name would bring back his memories and cause his power to go out of control, changed his name to Rotaro by adding a line to the kana changing "ko" to "ro".