The air in the underworld thrummed with a feverish, celebratory dread. It was the 15th Cycle Anniversary of the reign of the Great Demon King Satan, and the sprawling obsidian plaza before the royal palace was a seething ocean of infernal subjects. Imps and hellhounds jostled with hellknights, succubi with incubi shimmered beside hulking, magma-skinned brutes, and the air was thick with the scent of sulfur, incense, and anticipation. This was no mere festival; it was a vital reaffirmation of power. Today, before the eyes of all hell, Satan would once again summon the Mythical Beast, the primordial patron of all true Demon Kings, proving his worth and cementing his rule for the cycle to come.

High above the murmuring masses, upon a balcony carved from a single, monstrous vertebra of a forgotten god, a figure emerged. Silence fell like a guillotine. Satan, the Demon King, surveyed his domain. His form was one of terrible elegance—broad-shouldered and clad in armor that seemed to drink the dim, crimson light, his crown a jagged silhouette against the ever-stormy sky. A confident, almost lazy smile played on his lips. This was a well-rehearsed dance, performed flawlessly for millennia.

"The hour is struck!" His voice, amplified by raw power and ancient magic, rolled over the crowd like tectonic plates shifting. It was not a shout, but a declaration that vibrated in the very bones of his listeners. "Let the 15th Cycle commence!"

With a theatrical flourish born of absolute certainty, he turned from the balcony's edge. His hand swept through the air, claws tracing complex, burning sigils that hung in the space before him. A colossal demonic circle, a masterpiece of intricate, glowing runes, ignited upon the balcony floor. The air crackled, the temperature plummeted and then soared, and a pressure built that made lesser demons whimper. This was the foundation of his sovereignty. The Mythical Beast named 'Behemoth'—a dragon-like entity of primordial chaos, acknowledged even by the heavens as one of the oldest forces in existence. Only a true Demon King could tame it, and in riding it over his kingdom, he would weave his will into the very fabric of the underworld.

Satan's excited smile widened into a grin of raw, anticipatory triumph. This moment, the roar of the beast, the adulation of the crowd, the envious glances of the sneaking gods he knew watched from beyond—it was the ultimate narcotic. Every cycle, it was magnificent.

The summoning circle erupted in a pillar of blinding, blood-crimson light. It tore into the sky, a beacon of absolute power. The crowd held its breath, necks craned to see the first glimpse of scaled hide, the first earth-shattering beat of titanic wings.

The light died as suddenly as it came.

Not with a thunderous arrival, but with a soft, pathetic thud.

Where the majestic, world-ending form of the Mythical Beast should have stood, coiled in terrifying glory, there was only… a person. A mortal. You. Disheveled, wide-eyed, and looking profoundly, utterly out of place on the pristine, infernal marble.