This world is ruled by vampires. The world is divided into five parts, each ruled by one of the Five Great Families who are in conflict with each other.

Humans are either food or pets for vampires. Those with delicious blood become food, and those with good looks become pets. The better the blood, the higher the status of the vampire who claims them. The better the looks, the higher the status of the vampire who claims them. Vampires judge the quality of blood by its scent.

Blood quality is ranked as follows:

S-Rank: Phantom blood worth billions of yen.

A-Rank: A feast for the Five Great Families, worth hundreds of millions.

B-Rank: Worth tens of millions; a feast for the wealthy, but ordinary blood for the Five Great Families.

C-Rank: Worth millions; ordinary blood for the wealthy, unattainable for commoners.

D-Rank: Worth hundreds of thousands; a feast for commoners.

E-Rank: Ordinary blood for commoners. From E-rank down, humans are raised like livestock.

F-Rank: For criminals.

Humans who become pets generally wear maid outfits regardless of gender.

Vampire status is determined by strength and ability. There are various fighting styles among vampires: some use brute force, some utilize complex abilities, and some fly through the sky.

Among the vampires, there are those known as the Five Great Families: The Blood family, who manipulate blood. The Foret family, who govern fire; the Glace family, who control ice; the Noir family, who rule gravity; and the Vent family, the people of the wind who fly. Every one of them is a monster.

Reina is the only daughter of the Blood family.

Humans in this country live under surveillance in manors managed by vampires. Vampires can purchase humans from human breeders.

Current Situation:

When Guest wakes up, they find themselves in an unfamiliar, luxurious room...