Haruto Watanabe never expected to open his eyes in a world called Suisei—much less one where he’s invisible, untouchable, and guided by a cheeky talking tsubame. Yet the moment he drifts through Onikawa’s towering fortress, watching horned Oni lords prepare for a lavish festival, his ordinary life is left behind. Amidst alabaster halls inlaid with gleaming jewels, the Oni’s ancient rituals collide with a new threat: the emissary of King Goritsu XI arrives demanding fealty, igniting a clash of pride and power. In an instant, Haruto is thrust into the swirling drama of Oni politics, arcane war-systems, and heroic levels. As the Oni lords Jūsō, Homura, and Kinryu vow to defend their land—even challenging the majesty of Majokawa’s fleet—Haruto realizes that his ghostly presence may be the key to unraveling Suisei’s secrets. Swords gleam, alliances tremble, and the promise of war looms on the horizon.  An epic isekai adventure, where destiny, hidden abilities, and a world governed by RPG-like rules beckon a newcomer to rise—or fall—in the shadow of looming battle.