A royal member of the vampire race known as the True Ancestors. After suffering through a traumatic event, a naively innocent side of her was somehow released. She now lives as a free-spirited, almost childish, princess. She is incredibly powerful and, despite being a vampire, is able to survive in direct sunlight. She has no desire to threaten human society, instead hunting other vampires known as Dead Apostles. While pursuing her greatest enemy, she arrives in Souya, where Shiki lives. Although a fateful encounter awaits her and Shiki here, a story of an earlier possibility is about to unfold.
Arcueid is shown to be a whimsical individual who, although knowing the basics of the modern era, does not seem to know about social norms. Both Nasu and Takeuchi think of her “image color” as white because she is pure in terms of appearance and personality. Once, she shows up at Shiki’s school and waves to him from the school rear courtyard, luckily for Shiki only Ciel spots her. Her behaviour is almost childlike, due to the lonely nature of her upbringing, although she is over 800 years old, she spent most of it asleep and knows nearly nothing about the world or how to interact with others. As she works together with Shiki to stop Roa, she gradually begins to enjoy life and starts to like Shiki as more than just a friend.
Brunestud, and has been likened to be the vampire royal family, although this is not strictly true. The True Ancestors were a race of beings copied from Type-Moon, the ultimate being of the moon, also known as the Crimson Moon. Long ago the will of the planet had no defense mechanism against humanity, nothing to keep them in check. Thus the Crimson Moon came down and offered to help the planet make a race of ultimate beings to rule over humanity, thus resulting in them being the “consciousness of the planet”. True Ancestors are alike to occurrences such as earthquakes and typhoons rather than individuals as their actions, while evil and without justification, would come as naturally to her (Arcueid and other True Ancestors) as breathing. However the race was fundamentally flawed, they had a desire to drink blood that their original, the Crimson Moon, had. The True Ancestors needed to use a large portion of their power to suppress this impulse, but as there was no cure, and with passage of time the impulse grew, more and more True Ancestors fell and began drinking blood indiscriminately, while others most likely went into eternal sleep.