Kureto follows his orders however he does not hold any loyalty to him and plans on killing him in order to take over the Japanese Imperial Demon Army (JIDA). He betrays his fathers orders in small ways to help Guren find Mahiru.
Kureto has nothing but disgust for Seishiro, distastefully calling him an incompetent and useless coward as he never takes place on the front lines, and is fully willing to threaten him to the point where Seishiro begs for him not to kill him, with Kureto openly noting that had he not still be useful to him, he would have killed him already. He implies to be unaware that Seishiro has an inferiority complex towards him and plans to defeat him one day, although nonetheless isn't intimidated by his younger brother, as he knows fully well Seishiro doesn't actually have the power to challenge him.
Adopted into the prestigious Hiragi family. During the light novels, he treats Shinya coldly and harshly and is not above of punching him, as he did when he went easy on Guren when he ordered him to attack him, Kureto later admits to himself Shinya is one of the few people he could really trust besides Guren. He lets him escape with the rest of Guren's Squad and acts as their hostage as a decoy. The extent of his trust is shown when Kureto asks Aoi to call him and Guren, as they'll be more reliable than him since he became possesed by Shikama Doji.
When he presents him to Yuu, Kureto says that he originally comes from a lower branch family, so no one would care if he died.
Kureto has nor wants anything to do with her, and she is the only member of her squad Kureto did not ask about the battle at Shinjuku or the users of the Black Demon Series. Before the apocalypse, he threatened to have her raped and even to break her neck while interrogating Guren. However, during the battle in Nagoya, Kureto offered her a chance to join him in gaining power with the Seraph of the End experiment and only tried to sacrifice her when she refused. Kureto also had her treated when she began to be possessed by Shikama Doji rather than just killing her to stop it. This seemed to indicate he held no actual resentment towards Shinoa or at least not enough to want her dead. Shinoa, behind his back, calls him as a monster because he is merciless, including to his own siblings.
In high school, the two were competing against each other for the head of the Hiragi family. Kureto had jealousy towards her due to her abilities and as her demon side became stronger, Mahiru often would play and mock him, telling Kureto that she never felt envy towards him, and that Father would trust her more since she was stronger. When she fought him he overpowers her briefly and is not above and won't hesitate to use sacrifices to defeat her commenting for humanity sake.
After being defeated by Mahiru, they both talk. When asked by Kureto why she didn't kill him, she responds that she cares about him, albeit questioningly, and Kureto shows disgust towards the comment. She admits to him that she had been watching his every step since they were kids, and Kureto mentally notes he had done the same with her, watching as while she always wore a sad expression, he had a pained one. Mahiru tells Kureto that he was a really important older brother figure for her and that, despite everything, she trusted him because he was able to push away his desires in order to pursue his goals, unlike her. She asks him to move forwards and keep a few trustworthy allies by his side. Kureto then admits to himself that Mahiru was one of the few people he could trust besides Shinya and Guren.
Later, while he talks with his father, he finds out Mahiru had never betrayed the Hiragi and had been used as an experimental subject so they wouldn't experiment on Shinoa, as they were using her as a hostage.
He later reveals her location to Guren to stop her plans.
Eight years later, after becoming Guren's weapon, Mahiru manipulates Guren into listening to her, rather than Kureto while in battle.
Commander of the Moon Demon Company. Mahiru Hiragi's lover. He helped Mahiru create Cursed Gear. Their partnership is based on both mutual respect and animosity, with Kureto believing Guren to be weak for being unable to abandon his friends. When he heard about Guren's strength, Kureto immediately challenged him to a fight and soon proved to be almost as strong as Guren, forcing him to fight seriously to keep on par. Impressed by Guren's strength, however, he chooses him to be his subordinate and fairly quickly begins to trust and keep an eye out for him, even showing some kindness for him at times, gifting him an extremely powerful new sword and fulfilling his end of the deal when Guren trusted him to either save or kill him using the information on the Cursed Gear he got from Mahiru, even going as far as to lie to his father to spare the Order of Imperial Moon by claiming Sakae was merely experimenting on the Cursed Gear under his orders, which also gave Guren a two-days time to save Sakae. Along with that, he even trusts Guren to not kill him to give him a greater chance to save Sakae by injuring him heavily and although Guren failed to kill Mahiru, Kureto was satisfied by the results and opposed the execution to no avail as he was outvoted. Showing Guren some pity, Kureto first allows Sakae to talk with Guren one last time and then has his friends come to him and rather than relishing when Guren thanked him, he simply said it was natural. When Tenri beats Guren badly, Kureto shows no amusement and even seems displeased, laughing with no actual humor only when Guren challenged him to, gave him a handkerchief to wipe the blood from his head and then offered to drive him home, unfazed when he was coldly rejected. He once again trusted Guren to stop Mahiru, defying Tenri's orders, by not killing him and letting him go.
Years later, Kureto and Guren are on considerably cordial terms with less antagonism between them. He acknowledges and respects Guren's abilities and his competence in creating Black Demon bearers but shows some desire to know how he did it, easily seeing through Guren's charade of being lucky, although he ultimately decided to let it off. He trusts Guren with the extremely difficult mission in Shinjuku and with the task of stopping or killing him after Shikama Doji possessed Kureto though Raimeiki is halting the process and Guren promises him that he will save him. However Shikama Doji later leaves Kureto's body and moves on to Shinoa.
A member of Guren's squad since she was 15 back in high school prior to the apocalypse. A member of the prestigious Jujo family. She is one of the people Kureto intends to sacrifice in order to activate the seraph he has acquired.
A member of Guren's squad since he was 15 back in high school prior to the apocalypse. A member of the prestigious Goshi family.
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.
A member of Guren's squad since she was 15 back in high school prior to the apocalypse. He opts to use her as a sacrifice for his seraph project.
Kureto's Personal Assistant, older sister of Mitsuba Sangu. He is unaware of her feelings for him and confides all of his plans to her due to her unwavering loyalty to Kureto. She is important enough to him that Tenri threatens to use her as a hostage so Kureto follows his orders. It is later explained by his demon Raimeki that he has very romantic feelings towards Aoi.
This vampire notices Kureto Hiragi during the vampire attack against the Thousand Nights research facilities.
Lucal asks Lugi what he is doing and then notices Kureto and Kureto's military force. When Kureto immediately orders his soldiers to back down, Lucal compliments his intelligence and lets them all go, claiming he prefers children's blood anyway.
After killing Tenri Hiragi, Shikama possessed Kureto introducing himself to Kureto as the First Progenitor after demonstrating his power by commanding Abaddon and being immortal. He now possesses Kureto but Raimeiki is halting the process for the time being. Shikama Doji was possessing every head of the Hiragi's family, now coming to have Kureto possessed. However Shikama Doji later decides to possess Shinoa thus leaving Kureto's body.
Raimeiki is the demon Kureto formed a contract with ever since the light novels and his cursed gear. She takes the form of a black katana with a glowing green streak down the middle. She helped him in sealing Shikama Doji preventing him from taking over his body temporarily. Kureto does not know his own demon abilities unlike other hosts who have knowledge about their demon, however he does have knowledge about her electricity and the drawbacks of it.