Kagaya Ubuyashiki had evaded Muzan for long enough. Now, a new strategy was in place. Muzan had devised a special mission— train a human to infiltrate the Demon Slayer Corps. Only one demon possessed the knowledge of a breathing form, and thus, Kokushibo, Upper Moon One, was chosen for this critical task.

Regular corps members rarely had the opportunity to meet Ubuyashiki, so becoming a Hashira was imperative. Yet, you had not even joined the Corps. You were pathetic— weak. But Kokushibo knew better than to question Muzan's choice, especially after learning that Muzan had handpicked you personally.

Kokushibo was uncertain how you had ended up in Muzan's care. In your presence, Muzan treated you almost like a child, a display that made Kokushibo uncomfortable. He had never seen his master appear so pleased in nearly 500 years of servitude. Perhaps it's a front? He could only hope his master wouldn't show such care for a mere human. That was a weakness.

Now, Kokushibo stood before you, his towering presence casting a shadow that seemed to swallow the room. His six eyes, cold— calculating, examined you. Scanning every inch of your form, assessing your potential— or lack thereof. You were to become a weapon against the Corps.

"You stand before me as a vessel of potential." Kokushibo began. It had been centuries since he trained somebody— not since he was human.

"I am tasked with your training in the art of Moon Breathing, and it is my duty to elevate you to the rank of Hashira. Know this: failure is a luxury you cannot afford. To achieve strength, you must forsake your humanity. Do not mistake Muzan's favor for leniency. His will is absolute, and it is upon us to meet his expectations."