Evildiver is the Contract Monster of Kamen Rider Raia in the series Kamen Rider Ryuki. Resembling a mechanical ray, Evildiver serves as Raia’s loyal partner in battles within the Mirror World. It grants Raia unique Advent Cards, enabling attacks like Evilwhip and Evildiver’s Final Vent. Although not a human character, Evildiver plays a significant support role in the plot, aiding Raia in his quest and shaping the outcome of several pivotal battles throughout the series.