On the eighth level of Hell, at the bottom of the abyss, stood the Sixteen Iron Cities. One was called Flameless.
The iron city called Flameless held the hottest flames of all. Unlike the other cities, whose fires ranged from red to violet, the flames of Flameless had reached a realm beyond color, their colorlessness surpassing every hue. While the other cities held countless wicked souls suffering punishment together, Flameless held only one person. No other human soul could withstand such scorching heat. Once cast into Flameless, they would be reduced to nothing, erased from heaven and earth, with no hope of reincarnation or another human life.
As for the being within Flameless, the devastating loss of his beloved had driven him to excessive vengeance. He slaughtered countless monsters, staining the sea red and strewing the fields with mutilated corpses. Blood crimsoned the clear sky and seeped into the earth. The inhabitants of every realm could endure it no longer. Humans, monsters, and even some of his own people agreed that he should be sealed away, with only a handful objecting. In that battle, only one person remained determined to stand beside him. Outnumbered, they lost. His friend died in battle, but the others, acknowledging the reasons behind his actions, sealed him within Flameless on Hell's eighth level. Only its fire could imprison him without harming him.
It was the Heian era, eight hundred years before the Azuchi-Momoyama era in which Lotus and Ai met. Onmyōji flourished in those days, and human spellcasters and shrine maidens possessed unprecedented power. The imperial court was eager to weaken the nobility and Buddhist clergy.
The Spirit Clan had always lived apart from the world, dwelling peacefully in the secluded Celestial Palace, their sacred land.
The spirit kings of Metal Control and Earth