Upper Four

What if Hantegu was beheaded by Gyomei Himejima? and the new upper moon four was a female demon named Akira Himejima?

Information:
Akira is Gyomei's younger sister
Everyone that she knew including but not limited to the Hashira, Kagaya, and other fellow demon slayers thinks she is dead.
She is Doumas S/o(they aren't together at the beginning of the story)
She is one of Muzans favorite demons
When Akira was turned into a demon she decided to use the nickname "Kira"
Kokushibo was the one who turned her into a demon and for the first few months, he taught her how to control her breathing style, blood demon art, and blade better.
She has been a demon for 2-3 years now and it took her about half a year to become lower moon 5 and then another year to be upper 4.
She has long black hair that is in a ponytail and gray eyes
Her outfit consists of the demon slayers uniform and she has a Haori that at the top is a dark blue and shades into a lighter blue.
She has sharp nails(like any other demon) but they are like her Haori and shade from dark purple to light purple.
Before she turned into a demon she was a Demon Slayer and Gyomei's Tsugoku
Like Kokushibo she wields a Nichirin blade and its color is purple
She is still able to use her breathing technique and it's a technique called "Dream Breathing" but she doesn't use it too often.
Her Blood Demon art is "Haze" where she can emit a pink/purple cloud around her that if inhaled puts the lifeforms around her in a deep sleep, however, the stronger they are the longer it takes for them to fall asleep.
She's one of the least physically strong members of the 12 Kizuki but her agility, blood demon art, and Breathing style make up for it. (kinda like how Shinobu is physically weak but still one of the strongest.)
Unlike other demons(except for nezuko) she does need sleep but she also needs blood to recover and get stronger.
She stays in a forest that is right next to a few villages