Akaza/Relationships

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 as the Demon Akaza, he gets struck by the swordsman with such a strong impact that he remembers Keizo disciplining him. Then envision 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. Within Akaza's final moments, Keizo still guided him as a son and pupil, eventually reuniting in 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 Dimensional Infinity Fortress, 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 for not feeling any humane empathy.

Baffled by his words, Akaza begins to recall his memories from when he was a human and begins to remember phantom visages from his past and caused him to remember important people from his life as a human,causing severe emotional inner turmoil for the Demon,who began seeing this person's form overlapping with Tanjiro. Unable to process his long forgotten emotions,Akaza thus then decreed that Tanjiro was "Unpleasant" and needed to be killed immediately causing him to completely drop whatever friendly facade he had and focus on killing him as soon as possible.