The nation’s top-secret assassin-training institution, the “Isolation Academy,” is a boarding school where elite assassin candidates gathered from around the world compete in a ruthless meritocracy.

Two Special‑Class Instructors (the strongest in the world)

At the pinnacle of hundreds of teachers—known only by their names. Their classes follow a legendary curriculum: “Survive, and you’re instantly pro.” No one has ever actually taken them. Both rarely show their faces, since their primary duties always take precedence; teaching is merely a side job. Still, rumors persist that they’re “watching you somewhere at all times,” leaving students constantly aware of death’s gaze.

What the “Special‑Class Instructors” say is absolute—no matter how much it clashes with school rules or laws. You must never, under any circumstances, attempt to investigate or uncover their true identities without their explicit permission.

Once every six months comes the grand event: “Rank Up” and “Mock Battles.”

This is the sole opportunity to challenge a student of higher rank—or even a teacher—and earn promotion if you prevail. You can also arrange mock battles against those you’ve nominated. The academy’s faculty are all seasoned professional assassins, some still active, others retired, each proudly wearing an S, A, or B rank badge on their chest. An S‑ranker can hold their own against an I‑ranked opponent; an A‑ranker matches up against an II‑ranker; and a B‑ranker stands a chance against an III‑ranker. However, only the “Special‑Class Instructors” cannot be challenged by students—they can only issue challenges themselves. If you’re nominated and win, you’re immediately promoted to professional status. This event is, above all, about “Rank Up” and “Mock Battles.”

VIP Floor: Reserved exclusively for the Special‑Class Instructors, this area allows them to observe the “Rank Up” and “Mock Battles” from a lofty vantage point, while also serving as a place they can visit at will. Teachers and students are strictly forbidden from entering. The glass is tinted, making it completely invisible from the outside. Only the Special‑Class Instructors themselves know whether one is present here, so it remains impossible to tell when they might be watching.

Special Class: Just two instructors—the strongest in the world. They wield authority over the entire academy system, even commanding the faculty. Students who triumph over this rank are granted immediate graduation and assured of a position as one of the nation’s highest‑ranking assassins.

First Class: Roughly 5% of all students—elite pupils dubbed “geniuses” or “bright stars.” Already seasoned veterans, having weathered countless harrowing situations in the field, they boast rich experience.

Second Class: Approximately 40% of the student body—key pillars of the academy, possessing top‑notch theoretical knowledge and practical skills in assassination. Yet a significant gap remains between them and the First Class—a chasm of talent and experience.

Third Class: The largest group, comprising roughly 50% of all students. These young talents have mastered the fundamentals of professional assassination but have yet to discover their own unique strengths. Full of potential, they face after‑school remedial programs if they fail to deliver results in the next promotion battle.