HakuKoyu

HakuKoyu is the het ship between Akaza and Koyuki from the Demon Slayer fandom.

Canon
Hakuji and Koyuki first met when Koyuki’s father, Keizo, brought Hakuji home after he had beat up men on the street. At the time, Koyuki was a sickly and frail 13-year-old girl, who constantly needed to be nursed. While living in their home, Hakuji’s job was to care for Koyuki by cleaning her, changing her sheets and towels, and feeding her, because her mother had killed herself, not wanting to see Koyuki die; which Hakuji had experience with, due to caring for his ill father who had hung himself. While nursing Koyuki, Hakuji would talk with her, but easily became annoyed because she would start crying in the middle of their conversation. On one day, Hakuji told her that there would be a fireworks festival, but Koyuki told him that she wouldn’t be able to go because she was not able to move around by herself. Hakuji decided to stay home with her and said that they could go again another year. Later, the heir of the dojo next door was in love with Koyuki, but he had an extremely violent personality. He could never sympathize with her illness and during one meeting, he forced her to go outside on a day when she was in bad shape. She started having an asthma attack and he left her out of fear. Hakuji later discovered her alone and in pain, and saved her from dying.

After 3 years, Koyuki being 16 and Hakuji being 18, Koyuki was able to move around on her own and help Hakuji with everyday things. Keizo, the owner of the dojo, gave his position to Hakuji and pointed out that he could have Koyuki as well, causing both Hakuji and Koyuki to blush. One night, they both went to a fireworks festival and they started reminiscing of how they used to dream of going to one when they were younger. Koyuki then asks Hakuji if he would marry her, and Hakuji replies with saying that he will become stronger than anyone else and protect her for life. After hearing of Koyuki and Hakuji’s marriage, the heir of the dojo next door became enraged and gathered his disciples to fight Hakuji. However after failing to defeat him, they poisoned the water well at the dojo Hakuji, Koyuki, and Keizo resided in. While Hakuji was away visiting his fathers grave to tell him of his marriage, Koyuki and Keizo had both drank the water from the well and died. When Hakuji found their deceased bodies at the dojo, he sobbed as he held Koyuki’s body.

After grieving over Koyuki and Keizo’s deaths, Hakuji went into a blindsided rage to the point where he murdered every single member of the rivaling dojo that could be responsible for his wife and guardian’s death. He killed all 50 members with his bare hands, so hard that their faces couldn’t be recognizable and that their organs and bones were all crushed. After being turned into a demon against his will by Muzan Kibutsuji, he lost all of his human memories, but some still lingered, most of them being symbols of Koyuki. During his battle between Tanjiro and Giyuu, Hakuji, now “Akaza”, had been beheaded and was still trying to kill both of them, before he felt a spirit holding him back. He couldn’t recognize who it was due to his memories being wiped, but that spirit being Koyuki, persuaded him to come back, and to stop killing people. Akaza ended up killing himself by using his final technique and met Koyuki again in between heaven and hell. As he started looking at Koyuki, Akaza started regaining his memories, and reverted back to his human self. She held his face, welcoming back her husband as he hugged onto her tightly, and sobbed as he apologized for everything. Koyuki stated that she was glad that he remembered her and their family, as he sobbed more and they both burned in hell.

Fanon
HakuKoyu is a ship that isn’t as noticed by the fandom, unlike the other canon ships such as TanKana, ZenNezu, or ObaMitsu.

Fandom
https://archiveofourown.org/tags/Akaza*s*Koyuki%20(Kimetsu%20no%20Yaiba)/works

Trivia

 * Akaza’s pink hair resembles the color of Koyuki’s kimono
 * Akaza’s blood demon art forms the shape of a snowflake, the same snowflake as Koyuki’s kimono pattern and hairpins
 * Most of Akaza’s blood demon arts are named after fireworks, referencing his promise to Koyuki to see the fireworks, and where he got engaged to her
 * Akaza had gotten special permission from Muzan to not eat women, this reason being his lingering memories and love for koyuki
 * Akaza’s moral as a demon was to be the strongest, the same promise he made to koyuki at the festival