TV-Series
Description
Setsuna Kai, a fiercely determined 10-year-old with a hot-blooded streak and unyielding sense of justice, charges headfirst into danger, though his impulsive actions sometimes leave lingering regret. His spiky silver hair and sharp brown eyes mirror his energetic spirit, while his casual blue jacket adorned with gold zippers, athletic leggings, and worn running shoes signal a life spent chasing soccer balls and adrenaline. Orphaned early, he clings fiercely to his half-brother Nagahisa Kai—until demonic forces under Lucifer’s command abduct Nagahisa, thrusting Setsuna into a hidden war between angels and demons. Discovering his heritage as a Devil Child, a hybrid capable of entering the demonic Expanse, he arms himself with a Devil Riser gun and allies with Cool, a fiery Cerberus cub, to storm the demon realm.
His quest unravels buried truths: a spectral encounter with his mother reveals Nagahisa as his Angel Child half-brother and Lucifer as his father. This duality pits him against Nagahisa and the archangel Michael, who orchestrate Armageddon to reset existence. Torn between wielding Ragnarok’s apocalyptic power, ascending to godhood, or risking annihilation, Setsuna grapples with moral chaos.
Later, as a seasoned ally, he aids figures like Masaki Kuzuha in dismantling cursed conspiracies, showcasing tactical brilliance despite his limitation—lacking angelic energy to open divine portals. The manga expands his past: his mother’s death fuels his kendo discipline, while rivalry with Devil Child Mirai Kaname sparks an uneasy pact to thwart apocalypses. The Rainbow Horn, his mother’s relic, becomes a key to challenge tyrannical demons.
Persistent themes anchor his journey: resilience against brutal portal-induced injuries, emotional turmoil over fractured bonds, and alliances with redeemed demons like Jack Frost and Sphinx. These partnerships cement his role as a mediator between realms, balancing demonic lineage with human resolve to shield both worlds—even as his recklessness and strategic insight wage war within him.
His quest unravels buried truths: a spectral encounter with his mother reveals Nagahisa as his Angel Child half-brother and Lucifer as his father. This duality pits him against Nagahisa and the archangel Michael, who orchestrate Armageddon to reset existence. Torn between wielding Ragnarok’s apocalyptic power, ascending to godhood, or risking annihilation, Setsuna grapples with moral chaos.
Later, as a seasoned ally, he aids figures like Masaki Kuzuha in dismantling cursed conspiracies, showcasing tactical brilliance despite his limitation—lacking angelic energy to open divine portals. The manga expands his past: his mother’s death fuels his kendo discipline, while rivalry with Devil Child Mirai Kaname sparks an uneasy pact to thwart apocalypses. The Rainbow Horn, his mother’s relic, becomes a key to challenge tyrannical demons.
Persistent themes anchor his journey: resilience against brutal portal-induced injuries, emotional turmoil over fractured bonds, and alliances with redeemed demons like Jack Frost and Sphinx. These partnerships cement his role as a mediator between realms, balancing demonic lineage with human resolve to shield both worlds—even as his recklessness and strategic insight wage war within him.