Rash in nature, Masamune tends to act before thinking. He is very childish and bratty comparable to his age. Masamune has a crush on Hana and always tries to kiss her upon seeing her. Despite his childlike personality and free will nature, Masamune can be serious when he needs to be. He may act harsh but he's not merciless. He even went as far as allowing Gracia to live under Chikahito's request after she attacked them.