Hashira 

Water_snake = Giyu

Butterfly_Doc = Shinobu

Snake_mask = Obanai

Blind_groupFather = Gyiome (Kokushibo or Muichiro type for him)

FlamboyantSuperStar = Tengen

Mist_Amnesia = Muichiro

PansexualSimp = Mitsuri

Best_ofTheBest = Sanemi

DonutCannibal = Rengoku

Demons

Not_ MichaelJackson = Muzan

Moon_JustMoon = Kokushibo

ElsaBUTbetter = Douma

Cutest_Basketball = Akaza (Kyojuro set that as his name and Akaza forgot how to change it back)

Best_Pottery = Gyokko

GreenBrother = Karaku (forced to keep it like that because of Zohakuten instead of what he wants it as)

FuckOff_Angry = Sekido

Bird_Master = Urogi

I'mNo_Baby = Aizetsu

Hate_ItAlready = Zohakuten (they allow him to curse, they just don't want any NSFW stuff)

Wasn't_Me = Hantengu

Fuck_PrettyPeople = Gyutaro

Prettiest_ofAll = Daki

ThunderCat = Kaigaku 

BiwaLady = Nakemi

Everyone else

Eldest_Kamado = Tanjiro

LonelyLightning = Zenitsu

Boar_Head = Inosuke

Silent_Flower = Kanao

Best_Demon = Nezuko

FromAmerica = Genya

Dead people

MichaelJackson_Nightmare = Yoriichi

BetterMist_Boy = Yuichiro 

FoxMask = Sabito

PreciousBaby = Makomo

I'll be working on this when I have writers block on my other book "The Moon That Saved the Butterflies"  Also Giyu and Muichiro see Kokushibo as their father and so Giyu and Muichiro both call Koku dad