Katsuhiko Sagara is a character from the series Kamen Rider Agito. He is introduced as a passenger from the Akatsuki, a ship whose encounter with an unknown light awakened latent superhuman abilities in several individuals. His own powers are awakened by another being named Tetsuya. Sagara possesses psychokinetic abilities, allowing him to move and manipulate objects with his mind, in addition to a powerful regenerative healing factor that makes him very difficult to injure or kill.

In terms of personality, Sagara is manipulative and antagonistic. He demonstrates a willingness to use his powers for destructive ends and shows little regard for the lives of others. His role in the story is primarily that of an adversary. He manages to achieve a significant victory by killing the heroic rider known as Gills. Furthermore, he attempts to psychologically manipulate Mana, a young woman who also possesses growing powers, by trying to convince her that she cannot control her abilities and is a danger to those around her.

Key relationships in his story are largely adversarial. His primary targets include Gills, whom he kills, and Mana, whom he seeks to manipulate and deceive. His actions ultimately lead to his own demise; he is murdered by a creature known as the Crustata Palleo, an Lord. Regarding his development, as a character who appears in a limited number of episodes, his arc is more functional to the plot than focused on personal growth. He is depicted purely as a threat whose actions have major consequences, such as the death of a primary protagonist, before he is eliminated by a greater force. His notable abilities, as demonstrated, include psychokinesis for offensive and defensive purposes and a regenerative healing factor that makes him exceptionally resilient in combat.