Shinoa Hiiragi

The heroine of the manga. Captain of the Moon Demon Company Shinoa Hiiragi Squad. Her rank is Sergeant. Born on December 25th. She is 15 years old. Her demon weapon is a large scythe called "Shikama Dōji."

She ties her hair with a large dark purple ribbon at the back. She always has a smile on her face and never shows her true feelings. She enjoys interesting things and sometimes plays pranks or deliberately leaves situations unresolved for amusement. For a time, she was tasked by Guren to monitor Yuuichirou while also being his classmate. Although trusted by her superior Guren, she is often criticized for her poor crisis management skills and lack of diligence in her work.

She is a direct descendant of the Hiiragi family, which rules the Japanese Imperial Demon Army, and the younger sister of Mahiru Hiiragi. Like her sister, she has harbored a demon within her since birth, and her physical abilities and talent in sorcery are exceptional even within the Imperial Demon Army. She is an excellent test subject, and although she is unaware of it, both Mahiru and Shikama Dōji consider her to be more talented than Mahiru. To avoid getting entangled in family matters, she repeatedly refuses promotion orders and does not seek a rank higher than Sergeant. She claims to be abandoned by the central authority due to her sister's betrayal of the Hiiragi family and has never met her biological father, Tenri. Her biological mother was a distinguished follower of the Imperial Demons, the predecessor of the Imperial Demon Army, but her brain could not withstand the curse and burst at the time of Shinoa's birth, resulting in her death. Her relationships with her siblings are indifferent; she highly regards the abilities and talents of her half-brother Kureto and her biological sister Mahiru, calling them "monsters" and "geniuses," but does not trust their humanity.

Having never been needed by anyone since birth, she has a cold personality. However, being needed as a comrade by Yuuichirou, she decides to respond to that and fulfills her duties as a captain with the determination not to let her comrades die.

During the Nagoya battle, she successfully defeats the Fifteenth Progenitor, Lucal, along with Narumi's squad, but is forced to retreat due to the overwhelming power of the Thirteenth Progenitor, Crowley. During the retreat, she encounters Mikaela and entrusts Yuuichirou to him, which causes resentment among her comrades. Later, at Nagoya Airport, she witnesses the transformed Mirai due to the "Seraph of the End" experiment, sees many Imperial Demon Army soldiers massacred, and decides to defect with her entire squad and Makoto after Guren is completely taken over by Mahiru.

She harbors romantic feelings for Yuuichirou, and when Shikama Dōji points out and tries to exploit her lowered emotional defenses, she forcibly blocks him. However, after returning to the Imperial Demon Army, she opens her heart's door to save Yuuichirou from Shikama Dōji, which leads to the beginning of her transformation into a vampire. Just before being killed by Ferid as a method to stop the transformation, she is taken over by Shikama Dōji and fights against Lest Karr. However, with the help of Guren, Mahiru, and the three Cursed Gears, Shikama Dōji is sealed, and she regains consciousness.