Kai, who possesses unique abilities, was protected by the organization ASHURUM along with his ailing sister Hikaru. After being scouted by Eiji, Kai joined the ASHURUM special force AESES and underwent rigorous training to develop his skills. Despite his growth, Kai continued to visit Hikaru at the organization's hospital, where her condition unfortunately remained unchanged. A year later, with his abilities significantly enhanced, Kai decided to leave the organization.