Jinta and his younger sister Suzune are taken in by Kadono, a mountain village whose sentinel raises them alongside his own daughter, Shirayuki. Years later Jinta earns the sentinel's post himself, guarding Shirayuki after she is named Itsukihime, the village's shrine maiden. Then a demon in the nearby forest leaves him unaging and speaks of a ruler of all demonkind who will arise a hundred and seventy years on. Carried from the Edo period into the Heisei era, Jinta keeps hunting demons and keeps asking why he holds a sword at all. This manga adapts the original light novel.