This new Ubuyashiki Household members was basically leading the Demon Slayer Corps because the the days out of antiquety and then have went on to do this getting 1000 ages in their goal to kill the Devil Progenitor. On account of them as being the fundamental ringleaders of Devil Slayer Corps, Muzan significantly despises the brand new Ubuyashiki Relatives as well as many years, made it one of his true most readily useful prioraties to eliminate the entire clan and you will prevent their bloodline to permenently rid regarding himself of Demon Slayer Corps.
Because the found by the Kagaya Ubuyashiki, the Ubuyashiki relatives themselves are actually connected with Muzan of the bloodstream, with these people being the descendants away from his family relations out-of one thousand in years past. According to Kagaya, brand new Ubuyashiki bloodline is cursed in order to have put the fresh Devil Progenitor as well as the kids born in their clan try stated in order to was indeed sickly and you will weakened, perishing before they certainly were even adult. Out of next and that forward, the newest Ubuyashiki household members do receive their spouses chose in their 
eyes of the Priests, and because after that, when you’re people produced to the clan nonetheless died before they truly became 30, these were now at least, significantly more resistent in order to demise.
However regardless of this bloodstream link to your, Muzan himself shown zero mercy neither mental accessory into family unit members and you may rather states to really become sickened from the her or him, because seen while in the their talk which have Kagaya, in which the guy teased your and his awesome household members due to their many years enough time take care of so you can kill your.
12 Kizuki
Muzan holds these types of Demons within the quite a top esteem than the others, going for a larger percentage of his blood to boost its efforts. Even after favoring him or her over typical Demons, Muzan tends to demonstrate that the guy prefers top of the Ranks compared for the Down Ranking. It is confirmed whenever Muzan killed from the Demons into the Straight down Positions conference away from frustration adopting the Rui’s beat, along with his issue of the failure so you can victory contrary to the Devil Slayers as well as their visible incapacity to beat new Hashira’s of Corps and you will experienced these to feel conceited, negligent downfalls on account of them as excessively convinced in the fact that they turned into Straight down Ranks. Fundamentally, he viewed these since expendable gadgets and once emerging of their tissue cocoon to face the fresh Demon Slayer Corp, admonished these to be ineffective just before claiming that he by yourself will eliminate the Demon Slayers.
Kokushibo
Muzan very first came across your when he are also known as Michikatsu Tsugikuni, the latter had long desired to be due to the fact strong as their sister however, failed, and additionally dreading his forthcoming close passing from the results brand new Devil Slayer Mark. Muzan persuaded your to change, listing they might one another win, as he you will live forever and start to become more powerful while Muzan create get a breath Layout playing with devil.
He was perhaps among the nearest so you’re able to Muzan, which seen him once the a bit of a corporate lover. [5] Subsequently, Kokushibo became intensely dedicated to help you Muzan, acting as an enthusiastic enforcer towards the ladder the guy founded among Higher Positions, given that revealed as he punished and threatened Akaza to possess attacking Doma. Kokushibo and you will Muzan was in fact as one responsible for nearly eradicating Sunlight Breathing totally, following the latter’s find on former’s sis Yoriichi Tsugikuni.
Daki and you can Gyutaro
Muzan try proven to enjoys a positive learn-servant connection with Daki, since more youthful Demoness seemingly worships and you will admires the fresh Devil Progenitor immensely, fervently clinging for each each one-one from his conditions and you may performing this lady best possible to-do the new opportunities the guy offers the lady.