Yuichiro is a boy who escaped from the city of vampire. He holds intense hatred against vampires who killed his family, and enlisted in the Japanese Imperial Demon Army for vampire extermination. He is not always a good team player, but is kind and caring deep inside.

Mikaela is the 2nd remaining survivor of the Hyakuya Orphanage, and best friend of Yuichiro. He was thought to have died when escaping from the city of vampire, but was alive and turned into a vampire. He fights to rescue Yuichiro who is been used by humans.

Guren is Lieutenant Colonel of the “The Moon Demon Company”, Vampire Extermination Unit of the Japanese Imperial Demon Army. He has led Yuichiro to join the Japanese Imperial Demon Army after he escaped the city of vampire. He is secretly attempting something to reform the Imperial Demon Army governed by the Hiragi Family.

Ferid is the man who killed Yuichiro's family when they tried to escape the city of vampire. As a Seventh Progenitor vampire, he has much power but many times, he speaks nonsense. He seems to be plotting something with human behind everyone's back.

Shinoa is the Squad Leader of “The Moon Demon Company”. Her origin is Hiragi Family who takes control of the Japanese Imperial Demon Army, and is the real sister of Mahiru Hiiragi who developed the Cursed Gear. Is a subordinate of Lieutenant Colonel Guren, and was appointed to supervise Yuichiro Hyakuya.

Yoichi is a member of the "The Moon Demon Company” fighting vampires with Yuichiro. His sister has been killed by a vampire, and joined the troop for revenge. Although he is kind-hearted, he has a strong will and stand up against difficulty at times of emergency.

Same as Yuichiro, Shiho belongs to the “The Moon Demon Company”. He is clear headed with excellent combat ability, but is cynical and is treated as a trouble maker among others. Has a sister ill in bed, and enlisted in the army in order to undergo the treatment.

Mitusuba is an elite who belongs to the Vampire Extermination Unit since 13 years old. Has known Shinoa for a long time. She thinks that she let a member die because of her selfishness, and since then focuses on teamwork during battle.