Iska, a teenage boy with tousled black hair, a lean build, and piercing gray eyes, wears a black combat uniform and cape. Once hailed as the Heavenly Empire’s youngest Saint Disciple, his life sentence for aiding the escape of Sisbell Lou Nebulis IX—a fledgling astral mage—ended with a negotiated release during wartime. The Empire coerced him into hunting the "Ice Calamity Witch" Aliceliese Lou Nebulis IX for freedom, though his true aim is to dismantle the century-long conflict between the Empire and Nebulis Sovereignty.

Renowned for a staunch aversion to violence, he spares astral mages, incapacitating or hiding them—a philosophy earning him the moniker "peace-loving war nut." Calm yet unyielding in battle, he devises tactical risks to shield allies and fulfill missions. Loyalty drives him to treasonous acts for those he considers family, such as concealing his captain Mismis Klass’s astral mage transformation.

Mentored by Crosswell Nes Lubigate, Iska wields dual Astral Swords: black and white blades forged from purified Star Crystals. The black blade nullifies astral magic; the white temporarily replicates blocked spells. Mismatched in length and hue, these swords cement his title as "Successor of Black Steel," embodying his role as a bridge between factions. His expertise counters astral mages through unparalleled swordsmanship and reflexes, though conventional fighters challenge his expertise.

Relationships shift dramatically: Aliceliese transitions from rival to ally through shared ideals of peace, sparking unspoken romantic tension. Sisbell, whose liberation forged an unexpected bond, allies with him against threats like the Eight Great Apostles and Elletear Lou Nebulis IX. Childhood companion Jhin Syulargun and unitmates remain pillars of trust, their safety outweighing obedience to authority.

Exposing the war’s origin—a conspiracy masterminded by the Eight Great Apostles to vilify astral mages—he unites with former foes to dismantle their machinations. His journey from disgraced prisoner to linchpin of unity highlights adaptability and resolve. Defying political peril to protect Sisbell underscores his defiance of oppression, rooted in shielding the vulnerable.

Across narratives, Iska balances duty with conscience, navigating complex alliances and reckoning with the fallout of his choices. His arc centers on relentless pursuit of peace, accepting personal sacrifice to ignite change in a fractured world.