Akaza/Relationships

Father
When he was human, Hakuji loved and cared for his ailing father, but since they could not afford his medication, Hakuji had to resort to stealing in order to afford his father's treatment. When his father discovered that Hakuji had been arrested and beaten for his crimes, he felt guilty and committed suicide. In his letter to Hakuji he mentioned that he "didn't want to live on if it meant stealing from people" and he felt remorseful for troubling Hakuji to care for him.

Hakuji grew frustrated and angry after his father's death, and proceeded to violently fight throughout the town, resulting in his exile. Hakuji would take his rage out on the townspeople, trying to make sense of why his father needed to die as oppose to anyone else, showing the immense emotional pain he was in over his father's death. Later on when Hakuji becomes engaged to Koyuki, He traveled all the way back to his hometown despite being banished, and visits his father's grave to inform him of his engagement.

When Akaza remembers his father in the afterlife, he immediately asks him if he is suffering, still showing concern over his health. He falls to his knees before his father and apologizes to him for continuing his life of crime as a Demon, displaying his remorse.

Koyuki
When Hakuji arrives at the Dojo, he is introduced to Keizo's daughter, Koyuki, and is told that he will be in charge of nursing her. Since he had experience caring for his father, Hakuji preformed minor tasks such as changing her towels and bedding, as well as assist her to move around. Although Koyuki needed to rely on his assistance to survive, she constantly felt sorry for taking his free time away from him.

Three years pass and the two grow closer to each other as Koyuki's health improves. One day, Keizo asks Hakuji to become his successor for the dojo and tells him that Koyuki said she liked him causing both of them to blush. When the pair went out to watch the fireworks, Koyuki reveals her feelings of wanting to give up on life, but by meeting Hakuji she became happy and wanted to live out her life. Following her confession, she proposes to Hakuji who agrees to grow strong and her for the rest of her life. However, before they are able to wed, Koyuki and her father are unexpectedly poisoned, and killed by the rival dojo. Her death caused Hakuji to go into a blinding rage, to the point where he killed 67 members of the rival dojo.

Following the massacre, Hakuji wandered aimlessly until Muzan discovered him and transformed him into a Demon. After his transformation, he lost his memories and once again seeked to become strong, not wanting continue living in a world without a family, Hakuji &mdash; now Akaza &mdash; resorted to committing pointless acts of carnage to ease his pain.

After Tanjiro managed to decapitate Akaza, he was about to regenerate and to strike back as ordered by Muzan. However, Koyuki's spiritual apparition appears before him and thanks him, saying that he has done enough. Akaza's spirit then reverts back to his human form as he cries and apologizes to Koyuki for failing to protect them. Koyuki tearfully welcomes Hakuji with open arms and the two embrace, as Koyuki seemingly accompanies Hakuji to hell.

Keizo
Following the death of his father, Hakuji goes on a rampage and begins to fight with a crowd of men. As a result of the commotion, Keizo is called to settle the fight and discovers that Hakuji has knocked all of the men unconscious. He attempts to recruit Hakuji as a student at his dojo after being impressed by his fighting skills, and notices the criminal brandings on his arms. Keizo comes to understand Hakuji's situation and promises Hakuji that he will be reborn as one of his students, showing his genuine concern for his well being. He further provokes Hakuji by challenging him to a fight, but when Hakuji attempts to attack Keizo, he is swiftly knocked out by the dojo instructor.

After defeating and seeing Hakuji's potential, Keizo happily invited him to become a pupil of his dojo and instructed him to become the caretaker of his sickly daughter. For the next couple of years, Hakuji proceeded to diligently train under Keizo's instruction and soon became well loved by his teacher to the point where he offered his daughter to marry Hakuji. Keizo's warm acceptance of Hakuji brings joy to his life and he begins to see Keizo as an inspirational father figure as well as a respected teacher.

However, upon learning of Keizo's and Koyuki's murder at the hands of the rival dojo, Hakuji once again falls into a homicidal rage and proceeds to brutally murder 67 members of the dojo. Their death affect him greatly to an extent that he doesn't attempt to fight back when Muzan converts him into a demon, even saying that "I don't care anymore, I don't care about anything." Displaying his realization that he had lost the most important people in his life, yet again.

During his battle against Tanjiro, Akaza gets punched by the swordsman with such an impact that he remembers Keizo disciplining him. The vision of his master causes Akaza to slightly regain his humanity and cease his will to fight. Keizo's spiritual apparition comes forth to remind Akaza once again that "even in death he will not forsake him" but that he must pay for the sins he has committed. Even within Akaza's final moments, Keizo still guided him as a son and pupil, eventually welcoming him to the afterlife.

Tanjiro Kamado
Upon first meeting Tanjiro, Akaza attempted to immediately kill him without engaging in battle, seeing him as a "weakling" not worthy of his attention. Later on, when Akaza successfully defeated Kyojuro Rengoku, he fled the scene in order to escape the sunrise, but was stabbed in the back with a blade thrown by Tanjiro. During that instance, Tanjiro began to call Akaza a coward for trying to escape while insulting Kyojuro claiming that he was the true winner of the battle.

Enraged by Tanjiro's comments, Akaza's veins can be seen visibly protruding through his skin as he solemnly specifies that he was running from the sun, not from the demon slayers. Later on, when Akaza finishes his meeting with Muzan, he angrily destroys the blade that was thrown at him into pieces. He envisions Tanjiro's face, and promises that he will "spill [his] brains" the next time they meet.

When they meet again in the Infinity Castle, Akaza excitedly ambushes Tanjiro and Giyu where he then proclaims that he's "surprised a weakling like [Tanjiro] is still alive." As the three of them proceed to engage in battle, Akaza expresses his delight to see that Tanjiro had improved vastly in skill and power compared to when they first met, and goes on to "praise" Kyojuro for dying in order to aid in Tanjiro's development. His comments enrage Tanjiro, who claims that he has no choice but to defeat Akaza in order to protect mankind and expresses his pity towards him, for not feeling any empathy as a Demon.

Baffled by his words, Akaza remembers a faint memory from his past of someone mentioning something similar to Tanjiro. The subtle memory causes Akaza to grow angry with Tanjiro, and he proceeds to launch a rush of attacks towards him. However, when Tanjiro manages to decapitate him, Akaza becomes furious and continues to attack them while trying to regenerate his head.

His mind becomes foggy as he undergoes an inner conflict, and ends up getting punched in the face by Tanjiro. The impact of the punch, causes Akaza to remember his beloved teacher and the morals he was taught as a student. As a result, Akaza decides to sacrifice himself instead of killing the Demon Slayers and uses an attack on himself. Having witnessed Akaza's attempt to destroy himself, Tanjiro realizes that Akaza had smiled at him, and emitted the scent of gratitude towards him.

Muzan Kibutsuji
Muzan hears word of a "Demon" slaughtering members of a dojo nearby, but doesn't recall sending one to that area so he sets out to investigate. Upon travelling to the location, he discovers a human &mdash; Hakuji &mdash;soaked in blood and decides to utilize him as a Demon for his needs.

Following his first encounter with Tanjiro, Akaza meets with Muzan to report the events which had occurred. He informs the Demon Lord that he had defeated a Hashira, but failed to gather any information regarding the Blue Spider Lily which infuriates Muzan. He proceeds to berate Akaza for being a failure and cruelly tortures him by destroying his skin until he begins to bleed. However, Akaza maintains his composure and continues to bow before Muzan.

At the Upper Moon Meeting, Akaza immediately kneels before Muzan and refers to him as "Lord" showing his respect towards him. When Doma loiters around following the conclusion of the meeting, Akaza becomes angry at his disobedience and slashes his face.

Following his loss against Giyu and Tanjiro, Akaza regains his human memories and attempts to join his family in the afterlife. However Muzan tries to intervene and influences him to continue to fight, not wanting to lose another Demon to the Demon Slayer Corps. Despite his attempts to control him, Akaza manages to overcome Muzan's control and stops his body from regenerating.

Doma
During the Upper Moon Meeting, Akaza is approached by Doma and nonchalantly asked if he was worried about him, while putting his arm around him. However his bubbly personality does not sit well with Akaza, and he proceeds to command him to move, before destroying part of Doma's jaw.

Akaza's hatred for Doma can also be seen when he loses his patience and destroys Doma's head, after he loiters around following the end of the meeting. Doma alludes that Akaza's hatred towards him was due to the fact that he had surpassed him in rank, despite becoming a member of the Twelve Kizuki long after him.