Saitō/Relationships

Mahiru Hīragi
A teenage girl born from the Hīragi family. She joins the Hyakuya Sect to oppose her family. Saitō tells her to become a vampire and though refuses to turn her himself he helps Mahiru whilst also keeping his own objectives a secret.

Mikaela Hyakuya
A young seraph with high experimental potential. He acts as a leader toward the other orphans and is considered to be charming. He is half-Russian with blond hair and blue eyes. Saitō gives him money to buy ice cream. Mika's mother was a member of the Hyakuya Sect and gravely injured him by throwing him out of a moving vehicle. His parents died during the subsequent car crash and Saito delivers him to the Hyakuya orphanage.

Yūichirō Hyakuya
A young seraph who Saitō picks up after his mother attempts to burn him alive in their apartment and then lights herself on fire and commits suicide. His father was also abusive. Saitō takes him to the same orphanage as Mika a few minutes before the Apocalypse begins, and Yu fights him the whole way. At some point he orders his men at the Hyakuya Sect to infiltrate the building in Osaka where he is being held disguised as Kureto's scientists in order to capture him which he retrieve him successfully.

Guren Ichinose
The heir to the Ichinose family and one who opposes the Hīragi family. Saitō encounters him multiple times after a weak attempt to assassinate him, repeatedly offering an alliance persistently. He takes an interest to Guren after the catastrophe, and helped him with his tasks. Ferid later reveals that Saitō was only using Guren to his own benefits all along.

Sika Madu
Sika Madu, the First Progenitor, was the one who turned Saitō into a vampire. According to Saitō, he disregarded almost everyone in the vampire race except for Ashera Tepes, because he was bored and was not interested in them anymore. Later in Chapter 81, it was revealed that he possess a strong desire to obtain the first progenitor's attention and to be truly "seen" by him and even going to extreme lengths in order to accomplish this goal such as sacrificing his his subordinates of the Hyakuya Sect and his own sired vampires by stealing their life force to strengthen his own power in order to battle the First Progenitor on even ground and finally obtain his attention. As noted by his fellow Second Progenitor, Urd Geales he has been attempting to accomplish this goal since the early days of their immortal lives which he has continued to do so up to the present time and has gone great lengths to accomplish this goal.

Ferid Bathory
Saitō turned Ferid into a vampire. He disregarded Ferid because he did not act according to his expectations. He is ambushed by him and consequently loses his chance to defeat Guren and his demons, and the first progenitor. Found by him again, Saito assumes Ferid has a point in mind for wanting to kill him. Attacked with a sinful key, Saito uses his chains to restrain Ferid and says it was a mistake to turn him into a vampire, first and foremost since he was abnormal.

Crowley Eusford
Crowley was turned into a vampire using a vial containing Saitō's blood. It is unknown if Saitō is aware that Crowley is sired from him. He does not pay him much mind when he sees him with Ferid.

Krul Tepes
Saitō meets her while she is imprisoned in Ferid's mansion. She recognizes him as the one who tagged behind the First Progenitor and he talks to her about how the First was only interested in her brother Ashera Tepes.

Urd Geales
When Saitō was still Rigr Starford, he and Urd had a cordial friendly relationship as the eldest sired vampires, having shared and worked together to complete the First Progenitor's tasks, as when they were both given the duty to teach the newly sired Ashera Tepes about his new abilities and powers as a vampire and the new rules he must follow. The two are seen friendly bantering and arguing with each other in a familiar, friendly way. During this time, Urd is also seen having been slightly annoyed by Rigr's constant attempts to gain the first's attention in such instances where he worriedly/annoyingly aimed a look at him as he tried to talk to the first. Over the years, their relationship was estranged as Rigr had taken up the name of Saito and had left the Progenitor Council, as shown by how neither of them hesitated to fight the other when they met at Ferid's mansion while Krul was imprisoned. They both hold each other for their strong beliefs and desires in contempt and having known each other for so long understood each other incredibly, as Urd knew fully well that Riger only wanted to obtain the First's attention, which Urd seemed to pity but also be angry at him for, knowing fully well and accepting that the First's complete disinterest in them would never change, and Saito likewise abhors Urd for following the laws established by the First Progenitor so unquestionably.

Despite having been able to match him in their fight, it was revealed that Saito was actually wary, if not scared, of facing Urd, which he already indicated in their previous fight by asking Urd to stand down and fleeing instead of continuing to fight him and rather than confronting him directly, he send a large missile attack on Urd and his compatriots. After surviving the attack, Urd expresses confidence he can kill Saito if that is what he wishes, suggesting he may still be stronger than him. Saito also only saw Urd as a threat even when having to fight Ferid and Crowley while weakened and cursed when he couldn't get out before Urd arrived, saying that Urd was the last person he wanted help from. Although he reluctantly accepted Urd's aid, he made it clear he was looking for opportunities to slip away and was even pleased to see Crowley and Ferid nearly use the Sinful Key to take down Urd.

Urd in turn has shown active frustration in Rigr's actions and seems to demand from him to follow through on his original duties as a Second Progenitor and from his words as he had him captured, Urd would likely forcibly have him retake his position as a Progenitor in the Council if need be.

Basteya Irclu
A vampire noble who works under Saitō's commands, Basteya addresses him as lord Rigr Stafford and reveals that he is the one in control and they just simply play their part. This is evident further when he sided with an agent from the Hyakuya Sect to retreat from the battlefield. Basteya would obey Saitō even if they have to sacrifice themselves to increase his power, going as far as using a spell that would take of their life force at his command.

Caek Sanorium
A vampire noble and Saitō is his master. He sent him to meet with Guren as a guide so that Saitō and Guren could meet, he gave him a mission to test Guren strength by fighting him as well. At first Mahiru was hesitant if she and Guren should meet and talk, or fight each other. He obeys Saitō's orders without a question. His orders was to delay Guren's friends until Saitō and Guren are done with their conversation. He stated he understands very little of his goals, and everything he does doesn't make sense to him. He addresses him as Rigr Stafford, but he knew his name as Saitō as well.

Lest Karr
Although their actual relationship is unknown and it is still not shown if Rigr and Lest had any actual contact prior to his defection from the Progenitor Council, Lest is shown to actively fear and be wary of him due to knowing of the immense difference in power between him and Rigr and is shown to actively take open caution when dealing with him, behavior in stark difference to Lest's usual arrogant behavior even towards his fellow Progenitors.

Asuramaru
Originally a vampire Ashera Tepes, Saitō along with Urd Geales were witnesses when the first progenitor, Sika Madu disappeared with him 1,000 years ago. Sika intentionally turned him into a demon against his sister Krul Tepes wishes which he ignores. He and Urd waited for Ashera to wake up soon after his transformation, Saitō says along with Urd that they will have to teach him control his thirst for blood.

Mahiru-no-Yo
The demon that resides in Guren sword, he only met her once when she materialized next to Saitō after he throws a sinful key at her throat. It seemed to Mahiru-no-Yo that she had no memory of him prior to becoming Guren's Cursed Gear.