Daido Katsumi is the main antagonist in the Kamen Rider W universe, particularly in the movie 'Kamen Rider W Forever: A to Z/The Gaia Memories of Fate.' Known as Kamen Rider Eternal, he is the leader of the terrorist group NEVER. Driven by a tragic past, Daido seeks revenge and aims to plunge the world into chaos using the powerful T2 Gaia Memories. His formidable combat skills and cold demeanor make him a memorable and complex villain within the Kamen Rider franchise.