Sakamaki Reiji

Reiji is the second eldest son of the Sakamaki household. Reiji and his older brother, Shu, are the sons of Beatrix, the second wife of Karlheinz, the Vampire King. Reiji has refined manners. Though he might have a polite, sophisticated way of speaking (which the creators describe to be "butler-like"), his words tend to come with a biting edge. He values rules and demands that they are followed by others, but he creates many strange rules. Despite how rigid he may seem, he still has some sense of humor (albeit a dry one).

Although Reiji is the second son, he takes it upon himself to keep the house tidy, to manage household affairs, and to keep his brothers in line. His role in the family combined with his seemingly polite, gentlemanly posture often causes him to appear more like the eldest instead of his older brother Shu.

Shown by how he values rules, Reiji is a strict person towards both himself and those around him. He is an arrogant, prideful person who demands perfection and dislikes submitting to weakness. Though his words may be harsh, they shouldn't always be taken at face value. He is an extreme sadist like the rest of his brothers, and his particular phrase is schadenfreude (pleasure derived by someone from another person's misfortune). Sometimes he does or says something in order to get a reaction that amuses him.

Along with his passion for experimenting and making potions/drugs, he loves to collect tea sets and kitchenware. His brothers sometimes use Reiji's love for kitchenware to coerce him into cooking for them by saying that they'll use the kitchen themselves - his brothers have a penchant for destroying it when they use it. Due to his love for collecting, Ayato often calls him a tableware otaku.