Kirihiko Sudo is a prominent character in the series Kamen Rider W. He is the human identity of the R-Nasca Dopant, serving as one of the major antagonists in the early part of the series. Ambitious and sophisticated, Kirihiko is a high-ranking member of the Sonozaki Family, the organization distributing Gaia Memories in Fuuto City. Torn between his duties and his love for Saeko Sonozaki, Kirihiko's complex motivations and tragic arc make him a memorable and nuanced villain.