He is ambidextrous. He likes people-watching, cafes, and fantastical stories, while he dislikes having his clothes made fun of, and self-help books. Gentaro mainly uses the old-fashioned pronoun "shousei" (小生) to refer to himself. Due to his tendency to change his voice's pitch or sound to make characters, such as a princess or an old man, he sometimes uses pronouns as "watashi", "ore", "boku", "maro" or "warawa". Gentaro has a twin brother, however it is unknown which of the two are the oldest.