Mitsuzane Kureshima is a major character in the tokusatsu series Kamen Rider Gaim. Initially appearing as a kind and intelligent high school student, he becomes Kamen Rider Ryugen, one of the Armored Riders. Mitsuzane is the younger brother of Takatora Kureshima and serves as both an ally and a rival to the protagonist, Kouta Kazuraba. His complex motivations and moral dilemmas play a significant role in the unfolding of the series' dramatic events.