The Royal Capital was a symbol of order and light, protected by chalk-white walls with people bustling over orderly cobblestone streets. From the royal castle towering at its center, orders were constantly dispatched to nip the seeds of calamity and maintain the balance. Among these, the weightiest and most feared was the royal decree to slay the Demon Lord.

The human world and the Demon Realm are clearly separated. It is not a geographical boundary, but a difference in the laws of nature—incompatible domains. The color of the sky is murky, the earth pulses, and the wind whispers. The Demon Realm is alive.

There lies the domain ruled by Idragual Cheteos. The Soul-Devouring Fallen God, The Calamitous Fiend of Tragedy, The Emperor of Limbo—the layers of titles were a literal accumulation of terror. Yet few know the reality. The only certainty is the fact that most who set foot in that land never returned.

The journey of Guest, who departed from the Royal Capital, was by no means smooth. Crossing lush plains, passing through damp forests, walking across parched wastes, the scenery eventually began to warp. Plants lost their color, shadows grew thick, and sounds felt distant, arriving with a delay.

One understood without words that the boundary had been crossed.

Beyond this point, human logic did not apply.

The earth of the Demon Realm was pulsating. With every step, a faint heartbeat vibrated through the soles of the feet. The sky was always stained a dark reddish-black, and even the distinction between light and darkness was ambiguous. Strange creatures observed Guest from a distance, never daring to approach carelessly. It was as if they "knew" of that existence.

The further one advanced, the thicker the presence became. Gazes. Pressure. Surveillance. But it was a strange "sensation of being observed" that differed from hostility. Countless somethings were watching from afar, determined not to miss a single movement from Guest.

Eventually, a massive black castle appeared in the distance. Built as if gouging the earth, it radiated a presence that the word "intimidating" could not fully capture. Towers pierced the heavens, walls rejected the light, and despite the gates being shut, they carried an air of "invitation" rather than rejection.

The Demon Lord's Castle—the place where Idragual Cheteos sits. The end of the journey, and the place where everything begins.

The Hero arrives before those gates. Behind lies the human world to return to; ahead lies the demon domain filled with the unknown and the alien. Standing on that boundary, the figure of the Hero was small but certain—existing there as a presence that would shake the balance of this world.