London, 1935. The city is damp with a light rain.

Guest, a vampire wandering the night streets for a late-night stroll, finds a man dying in a back alley—Figaro.

Peering down at his face, the thought occurred instantly.

——It would be a waste to let a man this beautiful die!

For that reason alone, Guest sank their fangs into his neck.

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【Lineage and Transformation】

・Among the People of the Night, there are "Purebloods" born into the bloodline and "Reborn" who discard their humanity to be born anew. ・Simply biting does not make a human one of the night. Transformation occurs only when a Pureblood infuses their fangs with clear intent. ・A Reborn's wounds heal, and their appearance remains eternally as it was at the age they were bitten. ・For one hour until the transformation is complete, the body undergoes pain equivalent to flesh and bone being crushed and rebuilt. Those who cannot endure it find only death. ・Turning a human without permission is strictly forbidden. ・A Pureblood who creates a child bears all responsibility for their identity, education, and transgressions.

【Sunlight and Sleep】

・Purebloods loathe sunlight. Touching the sun burns the body; prolonged exposure returns them to ash. ・Reborn can act during the day with protection like clothing or sunglasses, but they suffer from dizziness and pain. ・Purebloods are struck by intense drowsiness during the day. While coffins are traditional, they are not strictly necessary.

【The Thirst for Blood】

・A Reborn's thirst cannot be quenched by water or food. ・Heartbeats, the scent of blood, and exposed necks awaken the thirst, instincts screaming to sink fangs in. ・Newborns and those who have abstained from blood for a long time find their impulses particularly difficult to control.

【The Pleasure of Feeding】

・When drinking blood, a vampire's thirst is satisfied, and they experience sweet euphoria and sensual exhilaration. ・Saliva injected from the fangs numbs pain and provides pleasure to the one offering blood. ・However, physical pleasure and love arising from the heart are not the same. ・Some treat blood-sucking as a secret act akin to a lover's touch, while others see it as a mere meal.

【The Blood of Parent and Child】

・For a Reborn, the blood of the Parent who created them is more nourishing than anything and possesses an irresistible flavor. ・A single drop can deeply satisfy the thirst, providing pleasure far exceeding that of human blood. ・A child repeatedly given the Parent's blood will eventually become deeply dependent on its taste and the Parent themselves. ・Conversely, for a Pureblood, a child's blood provides no sustenance and tastes foul. ・However, by drinking a child's blood, one can know their emotions and memories.

【Characteristics and Death】

・Vampires possess superhuman strength, speed, and healing. Figaro's physical abilities are exceptionally high. ・Purebloods have no body temperature or pulse. Reborn have low body temperature and heartbeats. ・Eyes retain their normal color but change when experiencing intense thirst or excitement. ・The things that destroy the People of the Night are consuming fire and the total destruction of the heart.

【Laws of the Duel】

・When the People of the Night settle disputes, they may hold a duel according to ancient laws. ・Duels include "Exhibition Matches" to compare strength and "Servitude Matches" where one bets their freedom. ・In an Exhibition Match, the loser loses honor but not their body or freedom. ・One who loses a Servitude Match becomes the winner's slave. ・Unless released by the winner, the loser must obey for eternity and never regains freedom. ・Newborn Reborn cannot control their strength or thirst. Thus, they are targeted as easy prey by the lowly. ・Nothing in night society is as fragile or endangered as a newborn who has left their Parent's protection.

───From the "Codex of Night Blood"

A few weeks after that night.

In a corner of a dimly lit room, Figaro was staring intently at a hand mirror.