OVA
Description
Originally a Nempo practitioner trained by Master Aguni Rai alongside Genichirou Izayoi, Rebi Ra learned to channel the universe's living chi. Dissatisfaction with his master's path and envy of Genichirou drove him to abandon Nempo. Seeking greater power, he embraced the Black Arts, selling his soul to demonic forces. In exchange for immense magical abilities and possession, he pledged to shatter the barriers between Earth and Hell, enabling demonic invasion and humanity's subjugation.

Empowered, Rebi Ra faced Genichirou in Shinjuku, Tokyo. His demonic might proved nearly invincible, leading to Genichirou's defeat and death. Rebi Ra then unleashed the catastrophic Demon Quake spell, devastating Shinjuku and transforming it into a demon-haunted wasteland, isolated from Tokyo by supernatural disasters and hostile creatures.

Over the next decade, Rebi Ra consolidated power within Shinjuku's ruins, preparing to open a permanent Hellgate. He summoned three powerful demon guardians. To ensure his ritual remained uninterrupted, he indirectly attacked the World Federation President using cursed plants. This strategically occupied his former master, Aguni Rai, who was forced to remain by the President's side to counter the lethal curse.

Ten years after the Demon Quake, Rebi Ra confronted Genichirou's son, Kyoya Izayoi, sent to stop him. Though Kyoya overcame the demon guardians, he was initially outmatched. Rebi Ra shattered Kyoya's weapon and cast him into a pit, capturing Sayaka Rama, the President's daughter, as a sacrificial offering.

Kyoya survived, retrieving his father's sword, Ashura, which amplified his chi. In their final battle, Rebi Ra attempted to use Sayaka as a shield, but her rescue by allies Mephisto and Chibi left him exposed. Kyoya channeled pure positive chi, negating the dark energies sustaining Rebi Ra and destroying his physical form.

Rebi Ra wielded potent magic: illusions, hypnotic suggestion, rapid regeneration, and immunity to conventional weapons. He fought with an obsidian sword featuring a red jewel in its hilt, capable of projecting destructive energy blasts. His martial skills, honed under Aguni Rai, made him a formidable swordsman even without sorcery. His powers, sustained entirely by demonic forces, rendered him impervious to all but the strongest opposing chi.

Rebi Ra's story is confined to the original novel and its 1988 OVA adaptation. Sequels such as "Demon Palace Babylon" and "Demon City Hunter" follow Kyoya, Sayaka, and Mephisto in new adventures without Rebi Ra, as his story concluded with his destruction. Spin-offs like "Demon City Blues" focus on new characters and threats, offering no further development or appearances of Rebi Ra.