Shiro Kobayashi

Shiro Kobayashi, demon name Diana, is one of the main characters in the series. Although she was originally human, she was turned into a vampire demon by Tsubaki Tachibana, her childhood friend. It is clearly stated that she is a fujoshi.

Magic and Abilities
Demon Drain: She can drain demon energy (spirit energy) from demons and anything with spirit energy including angels.

Spirit Energy Detection: Shiro is granted this ability by the vampire blood inside her. After being taught to use this ability by Tsubaki, she is able to sense the demonic aura of other demons. Later on, Shiro is shown to use this ability more effectively, as demonstrated when she was able to sense a pitch-black aura being emitted from someone in the Floating Garden.

High-Speed Regeneration: Shiro has the ability to regenerate at an astonishing rate. To some extent, her human form also seems to have a higher level of regeneration than that of a regular human, as she heals far quicker from fatigue or injury than any human being of average health and conditioning would be expected to.

Human Origins: Given that Shiro was originally human, she is unaffected by many things that vampires are weak against. She also exempts from the rule that prevents monsters from attacking humans, since she was once a human herself and still considers herself as one even after becoming a Vampire Demon.

Immortality: Since she's a vampire, she possesses immortality. Being able to live a long period of time and unable to die by conventional methods.