Kimetsu No Yaiba OC's

Fuku Asahi

Full name
Fuku Asahi.
Fuku, meaning 'lucky', and Asahi, meaning 'the morning son'

Nicknames
Well, none are pleasant. The Least insulting us simply 'isogashi-san', in reference to the fact that he's always too 'busy' to attend Hashira meetings

Age
17

Gender
Male, cis

Nationality
Japanese

Birthday
January 9th

Species
Demon

Occupation
Demon slayer, Hashira rank

Appearance
Not many really get to see Asahi, due to the fact that on the rare occasion he DOES show up, he's often covered head to toe. His traditional, daytime uniform consists of what is essentially a black turtleneck version of the slayer uniform, with the addition of a mask that obscures his lower face and a hood to cover the top. However, at night, the mask and hood are removed, showing off the.... Less than intimidating face he was stuck with.
Dazzling blue eyes and soft brown hair are what he was stuck with, complimented by the pale skin he's also gotten from the whole 'allergic to the sun' issue. Even moving away from his feminine face, the rest of his body was no luckier. Long legs, a thin frame, and that face often lead him to be confused with a woman, not helped by his voice, which also happens to be higher than the average man.

Personality
Despite how he looks, he isn't all too... well, soft. In fact, due to the fact that he's spent 17 years being referred to as a girl, he's developed an almost excessively masculine personality.
For him, that means competition and relatively unchecked aggression.
He's also capable of being sincere though, as his personality is naturally far more caring and maternal than he would like to admit.
If he ever IS nice to you, it's usually gonna be followed by some backhanded remark.

Family
He grew up with his older sister, Fuku Aoi. She was much nicer than him, sort of being referred to as 'the young mother' by everyone who lived nearby. She's where Asahi got his nicer side, and also his main reason for hunting demons today.

Friends

Kagaya Ubuyashiki
While it's only a friendship in the professional sense, Kagaya is the only member of the slayer corps that Asahi's ever actually spoken to. Like the other Hashira, he respects him deeply.

Enemies
As the other Hashira do, he considers the rest of the demons to be his enemies.
However, his hatred only truly extends to Muzan, and the rest still stand in a place where he may be willing not to hate them.

Breathing style
Before his demonic transformation, he practiced thunder breathing. He's since adapted it to fit his demon physiology a lot better, which he aptly dubbed 'demon breathing'.
He focuses on speed, obviously, and uses his supernatural regeneration and blood demon art to make his attacks as difficult to evade as possible.

Forms
First form: sorrow
The user aims for the throat with careful, controlled strikes. Made to be the most efficient, and quickest way to kill a demon

Second form: pain
The user breaks their bones to turn their limbs into a more flexible, elastic structure which can bend around obstacles to reach their target.
Second form: enhanced, agony. By healing at the last moment, the momentum of the flexible 'whip' is preserved whilst the added force of a solid surface is used, allowing more damage to be done.

Third form: torment
By ignoring the safety of those around, the user becomes more 'demon-like', with more speed, strength, and a higher will to cause pain. Essentially sort of a 'boost' that allows the user to become better at demon killing, however the extent of its use determines the after effects and how easy it is to calm down.

Weapons
Two sets of 'gloves'. They're both made of leather, with fingers constructed of Nichirin steel that allow him to fight in the way demons use best, hand to hand.
He also has a Nichirin knife, with a handle that can fold around. Pretty much just a fan knife, though he simply refers to it as his 'backup demon killer'

Demon blood art
His blood is simply incredibly unpleasant for other demons.
The scent of it is enough to be mildly distracting in small amounts, and anything more than a scratch can make demons begin to feel unpleasant, up to actual pain akin to a bad migraine. If any is CONSUMED, the effects are worsened to the level of horrible nausea.
If, somehow, he ever eats people, he would temporarily gain minute control over his blood, enough to harden it and use it as a knife. If he ever ate more, he'd even be able to control enough to use it from long distances and in higher quantities

Strengths
As a demon, he's given Hashira level abilities when it comes to strength and speed.
He also has naturally enhanced healing, capable of recovering from demon-induced injuries in moments.
He also possesses a nearly indomitable will, which allowed him to break free of Muzan's curse.

Weaknesses
As a demon, he's totally weak to sunlight.
And, unlike most other demons, any injury he gains from Nichirin takes FAR longer to heal than a wound he gets from a fellow demon. So much so that it's barely different to that of a human.
He's still a demon, and while he's capable satiating urges by forcing himself to eat demons, he's incredibly weakened by the fact he hasn't yet eaten human. It's entirely possible that continuing to not eat humans may weaken him further as years progress

Backstory
For the first 16 years of his life, things were pretty... bland. His mother had died during childbirth and his father had left them months before, leaving his older sister to care for him, even if she herself was only 17.
At 15 he decided to become a demon slayer, since he figured the ultimate kindness was rescuing people from man eating monsters, and his sister had raised him to be as kind as possible.
The first real event to happen since was when, just a few months into training, Muzan happened to pay them a visit. He would've killed Asahi, if it weren't for the fact that he'd actually managed to cut him while he was murdering Aoi, and that he was rather entertaining. He figured that a human who was still trying to kill him with a fist through the chest would've made a good upper 12, and that was true.
Or rather, would have been, if Asahi hadn't refused to obey.
Since then, he took part in the final selection and rode through the ranks pretty quickly due to the demon blood giving him abilities on par with a Hashira, and the fact that he didn't need to sleep allowing him to spend more time hunting.

Trivia
He's ambidextrous!
His ONLY goal is to kill Muzan, and being a demon sided with hunters means he's gonna live until he ends up confronting him
His favourite food is Chikara Udon