Guren Ichinose/Relationships

Special Private Yūichirō Hyakuya
When Yuchiro escapes Sanguinem, Guren takes him in and trains him as a soldier and secret weapon of the Japanese Imperial Demon Army. Guren knows he was a survivor of the Hyakuya Orphanage and saves him with the intention of experimenting on him. Yu is one of the seraph of the end. They develop a close relationship, and Guren acts as a father/mentor figure to Yu. He can make Yu transform by giving him a certain drug. Yu does not recall any of the experimentation or the transformation.

Sergeant Shinoa Hīragi
She is Guren's subordinate, and he assigns her to be the surveillance officer to both Yu and Kimizuki. Shinoa and Guren have a close relationship, and he says he would even let her kill him. Her sister is the demon inside Guren's sword. After learning that Guren has been experimenting on Yu, she asks him what his real intentions are. She becomes more concerned after learning that her sister may be influencing Guren behind the scenes. However, she remains loyal to Guren. A member of the prestigious Hiragi family.

Second Lieutenant Mitsuba Sangu
A soldier of the Moon Demon Company. She works under Shinoa as part of her squad. She disagreed with the decision to put her on a squad of rookies, but she later bonds with them. A member of the prestigious Sangu family.

Special Private Shiho Kimizuki
A soldier Guren experimented on. A wielder of a Black Demon. Although he does not want to work with Yu, Yu eventually wins him over. His sister, Mirai Kimizuki, is under hospital care. A member of Shinoa's squad.

Special Private Yoichi Saotome
A soldier Guren experimented on. A wielder of a Black Demon. He becomes Yu's first official friend. A member of Shinoa's squad.

Major General Shinya Hiragi
Although he was adopted into the prestigious Hiragi family, he is Guren's friend. He joins Guren without orders to help him in the attack on Nagoya.

Colonel Mito Jujo
A member of Guren's squad since she was 15 back in high school prior to the apocalypse. She appears to be tsundere toward Guren, but he is not interested. A member of the prestigious Jujo family.

Colonel Norito Goshi
A member of Guren's squad since he was 15 back in high school prior to the apocalypse. He enjoys making fun of Guren. A member of the prestigious Goshi family.

Second Lieutenant Sayuri Hanayori
A member of Guren's squad since she was 15 back in high school prior to the apocalypse. She teaches the students training in the Moon Demon Company. She has a crush on Guren.

Second Lieutenant Shigure Yukimi
A member of Guren's squad since she was 15 back in high school prior to the apocalypse. She does not speak often.

General Tenri Hīragi
Leader of the Japanese Imperial Demon Army as well as the Hiragi family, he looks down on Guren, who is from a lower branch family.

Lieutenant General Kureto Hiragi
The most likely to become the next leader of the JIDA. He and Guren have a rivalry dating back to high school. He respects Guren's intelligence and ability to produce bearers of Black Demons. He is ruthless and does not hesitate to torture hostages to make Guren or others talk. He suspects Guren is a spy for the vampires or may lead a coup against the Hiragi family, but he also says he trusts Guren and sends Guren on an extremely dangerous mission to Nagoya. A member of the prestigious Hiragi family.

Major General Seishiro Hiragi
A higher-ranking member of the JIDA, he calls Guren a loser and tells him to get lost. A member of the prestigious Hiragi family.

Mikaela Hyakuya
A powerful young vampire, who nearly kills Guren during the battle at Shinjuku. Guren calls him a naive brat. He turns out to be Yu's less-than-dead best friend and adopted family member. Guren agrees to help Yu get Mika back. A survivor of the Hyakuya orphanage and a seraph of the end.

Seventh Progenitor Ferid Bathory
An extremely powerful vampire, he works with Mika. Ferid plays with Guren on the battlefield at Shinjuku, though it's revealed later that he and Guren had been working together for some time, which explains a lot of the supposed coincidences throughout the story.

Third Progenitor Krul Tepes
Guren first met Krul once she arrived at Nagoya. Shortly after, Mahiru overtook his body and commanded Krul's assistance in an Owari no Serafu experiment at the airport. This told the ruler of Sanguinem that Guren and Mahiru, a woman she knew from eight years past, were connected.

Black Demon Mahiru Hirage/Mahiru-no-Yo
Guren's former fiancée and lover. Inventor of the Cursed Gear, she eventually becomes consumed with her research and becomes a demon. Guren kills her, and she becomes the demon in his sword. Shinoa Hiragi's elder sister. Despite her impressive genius, all she wants is to love Guren. Though while she might let Guren take the lead for the most part, she's not above possessing him to achieve her own ends, which she proved in Nagoya.

Black Demon Asuramaru
The demon Yuichiro Hyakuya makes a contract with. He has a connection to Guren.