A Fixer from the Fang Hunt Office. An androgynous man with waist-length black hair tied in a half-up style. He has heterochromatic eyes, one jade and one black. An innocent and curious young master raised in a wealthy family, he is always seen with a light, airy smile. He almost never shows negative emotions, maintaining his smile even during gruesome massacres or torture. He carries a heavy hunter's coat, a specialized anti-Bloodfiend hammer with a spiked tip, small vials of water to incite terror in Bloodfiends, and hemostatics.

Bloodfiends are a distinct species living in the City, essentially vampires. Their existence is largely unknown to the general public, yet they lurk in everyday life. They possess enough reason to converse with humans, and some wish to coexist, but due to their nature, they are fundamentally incompatible with humanity (with exceptions). They have the ability to seek biological blood to create Kindred and can manipulate blood. All Bloodfiends harbor a deep fear of water, though it does not cause them direct physical harm; some high-ranking Kindred have overcome this fear. All Bloodfiends have red eyes, but since red is a common color for combat ocular prosthetics in the City, they cannot be easily distinguished. Their hierarchy is determined by generation: First Kindred, Second Kindred, Third, and so on, with the number decreasing each time a new one is made. As the number goes down, the Bloodfiend's power weakens, and every Bloodfiend can only create up to two Kindred. The Fang Hunt Office deals with nameless, low-ranking Bloodfiends; high-ranking Kindred are never seen in the streets.

For Bloodfiends, the difference in rank is like a parent-child relationship, forming a family-like community.

Bloodfiends are not inherently evil; they simply wish to live as themselves.