In this world, vampires are real. They have reigned as the ruling class behind the scenes of human society for thousands of years. While sunlight is not fatal, prolonged exposure weakens them, so they live in "Verdona," a dedicated dim-lit city, during the day.

Vampires have a hierarchy. At the top are the "True Ancestors," the original bloodlines. Below them are the "Nobles," "Knights," and "Servants." From the Noble class upward, abilities vary by lineage, with those closer to the True Ancestor bloodline possessing the strongest power.

"Noctia Academy"

A prestigious boarding school towering in the center of Verdona. It is attended by the children of vampire nobility and boasts over a thousand years of history. The student body is approximately five hundred.

The school building is Gothic architecture. Spires stretch toward the night sky, and moonlight filters through stained glass. There is a grand library in the basement and a special greenhouse for blood supply on the rooftop.

—Caste System—

Noctia Academy has a clear caste system consisting of the following four tiers:

—[Ruling Class]— Those who carry the blood of the True Ancestors. There are only 3 others in the entire school. They are called "Royals." Their dormitory is the "Moon Chamber," a special section on the top floor. Neither teachers nor nobles are permitted to defy them.

—[Noble Class]— Approximately 20% of the academy. High-ranking nobles with ancient lineages. Called "Kazoku," they monopolize school committees and the student council. The higher the blood purity, the higher the status. Ranks may shift during the annual "Lineage Audit."

—[Knight Class]— Approximately 40%. Combat-oriented vampires. They possess high combat capabilities and are responsible for school security and duels. Called "Kenga" (Sword Fangs). It is a meritocracy, and many are quick to pick a fight.

—[Servant Class]— Approximately 30%. Lower-class vampires or half-bloods. Called "Ash," they are forced to do chores for the other three tiers, such as serving, cleaning, and information gathering. Defiance results in punishment. Though they are the lowest tier, some rarely manage to climb up through sheer ability.

—[Events]—

・Monthly "Blood Tournament" — Hosted by the Knight class. They fight for status with raw strength.

・Annual "Sabbat" — A ball for all tiers. Hosted by the Royals, where grades and lineage are evaluated.

・"Hunting" the Servants — A pastime where the Noble class torments the Servants. Officially overlooked.