Why did Muzan hate Ubuyashiki in Demon Slayer? Explained

The entire plot of Demon Slayer can be summed up in the existence of two certain individuals, Kagaya Ubuyashiki and Kibutsuji Muzan. They were the two leaders of the main opposing factions in the series, while Muzan, known as the Demon King, led the demons, the Ubuyashiki family established the Demon Slayer Corps to fight Muzan.

While the aforementioned reason might be able to portray the hatred between the two, some other vital reasons have led to this rivalry. Eager to know about the certain specifics between the two, many fans have asked the question, "Why did Muzan hate Ubuyashiki?" While the primary reason was their opposing nature towards each other, Muzan hated Ubuyashiki due to their family ties.

Disclaimer: This article contains spoilers from the Demon Slayer anime/manga.

The Demon Slayer Corps' history and objective in the series

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The Demon Slayer series portrays Kibutsuji Muzan as the King of the Demons, whose main objective was to acquire the blue spider lily to grant him immunity from the sunlight, and destroy the Demon Slayer Corps, who hunted him down. Kagaya Ubuyashiki's family was the one who established the Corps, providing the straightforward reasoning for Muzan's hate towards Ubuyashiki.

The Demon Slayer Corps was established thousands of years ago, from the current timeline of the story, during the Heian era. While the Corps constantly tried to and even to some extent destroy the demons made by Muzan, they were unsuccessful in reaching the Demon King himself. However, situations changed during the Sengoku era.

Soon after his wife was murdered by a demon, Yoriichi Tsugikuni, a gifted swordsman, enlisted in the Corps. He introduced the concept of Total Concentration Breathing among the Hashira, which became the biggest weapon in their arsenal for years to follow against the demons.

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While this provided a golden opportunity, distinctive marks started appearing on the slayers who used Breathing Forms, which inevitably shortened their lifespan. Meanwhile, a desperate Michikatsu, Yoriichi's brother, was approached by Muzan, offering him the power he was looking for in return for turning into a demon, which Michikatsu did and turned into Kokushibo.

However, shortly later, Yoriichi and Muzan came face to face. Yoriichi was able to almost kill the Demon King, with Muzan barely escaping and surviving. After the near-death experience, Muzan went into hiding for centuries until Yoriichi died, and he returned to destroy the Demon Slayer Corps, holding a grudge against Kagaya Ubuyashiki, the then-leader of the establishment.

The reason for Muzan hating Ubuyashiki personally

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Muzan was once a member of the Ubuyashiki family and was the first to be turned into a demon. While he turned into a demon, a curse was placed on the Ubuyashiki family, which is believed to have shortened lifespans and constant affliction from medical conditions. This curse upset Muzan as he deemed it was an effect of his transformation, adding to his hatred.

While Muzan aims to eradicate the Ubiyashiki bloodline to stop the functioning of the Corps, and their influence on others, he also harbors hatred towards them for simply showing weakness due to their medical ailments, and he being a part of such a family. This curse and the family's constant effort to eradicate him fuel his hatred even more.

Final thoughts

Kagaya Ubuyashiki sacrificing himself to buy time for the Hashira to defeat Muzan (Image via Ufotable)

While there might be many reasons for hatred between Muzan and Ubuyashiki, the main reason remains their positions as leaders of opposite sides. With the Ubuyashiki family remaining, Muzan could not advance with his objective to acquire the blue spider lily. Similarly, as long as Muzan remained, the Ubuyashiki family worked to oppose and stop him.

At the end of the Hashira Training arc, Ubuyashiki displayed the lengths he would go to stop Muzan by blowing himself and his wife alongside Muzan to provide an opportunity for the Hashira to arrive. As the anime moves towards the Infinity Castle arc, it is yet to be seen how fruitful his sacrifice was.

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About the author

Ribhu Ghosh is an Anime writer at Sportskeeda. With a degree in Journalism under the Calcutta University, his deep-rooted passion for anime and manga led him to pursue a career in writing about the same.

Along with his 6 years of experience as an illustrator and digital artist for various overseas anime studios and companies, he also aspires to write storylines. Ribhu's creative journey has been profoundly influenced by renowned mangakas such as Sui Ishida, Masashi Kishimoto, Kohei Horikoshi, and Koyoharu Gotouge.

Ribhu's enthusiasm for storytelling and illustration is evident in his meticulous approach to reporting. He values accuracy and relevance and always prioritizes thorough research.

If given a chance, he would return to 2014 and be a part of the Tokyo Ghoul series, as he admires its action scenes, story, plot twists, art, and adaptation from the manga.

When he's not writing, Ribhu enjoys illustrating, playing chess, and engaging in outdoor activities like badminton. His diverse interests extend to music, cooking, reading, and gaming, all of which complement his passion for entertainment.

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Edited by Tiasha