Demon Slayer: Muzan’s connection with the Ubuyashiki family explained

Tulisha srivastava
An image featuring Muzan and Kagaya from the Ubuyashiki family in Demon Slayer

The “Swordsmith Village Arc” of Demon Slayer hints that there is some connection between Muzan Kibutsuji and the Ubuyashiki family. Though they are sworn enemies, is there some deep history that the anime has yet to cover?

In Demon Slayer, the Demon Slayer Corps is the only organization that works to defeat the demon and protect the people. Their primary goal is to defeat Muzan and put an end to this terror. However, defeating that monster isn’t easy.

His strength is unlike any being in the world. Not only that, he hides behind the shadows and keeps changing his appearance. Tanjiro is the first demon slayer to encounter him. Not even the Hashiras ever got a chance to get a glimpse at him.

After Gyutaro’s defeat, Kagaya exclaims how this is an omen that they will defeat Muzan, the stain of their clan, in this generation. Kagaya is known to have a calm and gentle demeanour. Yet, he expresses his disgust toward Muzan so openly. As the leader of the Corps, Kagaya’s hatred toward Muzan is justified – but there’s more to it than that.

An image of Muzan from Demon Slayer

The history of the Demon Slayer Corps goes as far back as over a thousand years ago – when the first demon was born. Since then, the Ubuyashiki family has been leading the corps with the sole purpose of defeating Muzan. 

The hatred between Muzan and Ubuyashiki family runs deep, and they want to eliminate each other. However, Kagaya reveals that Muzan is a blood relative of the Ubuyashiki family. Since they are the descendants, it makes sense for the Ubuyashiki family to want to destroy the stain of their clan. 

Why Muzan’s death is the only hope for the Ubuyashiki family?

An image of Kagaya foreseeing Muzan's death in Demon Slayer

Because the Ubuyashiki bloodline was cursed for having produced the Demon Progenitor, all the children born into their clan would have weak and sickly bodies. The sickness is a genetic disorder that left the Ubuyashiki family with weak bodies and fewer than 30 years of life. 

While all boys will die before reaching the age of 30, girls will also suffer the same fate if they don’t marry and change their surnames by the age of 13. The clan has maintained their bloodline by marrying their heirs to women from families of priests. 

Centuries ago, the clan members consulted a priest to cure their curse. The answer they received was the reason behind their suffering, and it can only end with Muzan’s death. 

Demon Slayer can currently be streamed on Crunchyroll. In the meantime, check out our other TV hubs below:

Attack on Titan Season 4 Part 3 | Bleach Thousand Year Blood War Part 2 | Chainsaw Man Season 2 | BRZRKR movie | Jigokuraku Hell’s Paradise | Jujutsu Kaisen Season 2 | Sonic the Hedgehog 3 | Invincible Season 2