Riku is an anti-hero, turned later into one of the main heroes, of the Square Enix's video game series, Kingdom Hearts. A boy with average stamina, durability, and strenght, Riku is the childhood friend of Sora and Kairi, growing up alongside with them on Destiny Islands. Curious of the world outiside of their own, Riku's desire of exploring the unknown turned into nightmare as he meddled with the forces of darkness, turning against his friends as he did so. Since then, Riku realised his wrong ways, and attempts to make things right by following the path of dawn. He eventually reunited with his friends after the completion of hard trials and tests.
He is also involved in the villains tournament context, working under an employer, usually Maleficent. Ironically, his role in the video game series remains the same in the later events of the villains wars with himself being forced to serve the villains' designs, and trying to make amends and reunite with his friends, particularly with Sora.