One of the most powerful characters in Demon Slayer is the Upper Demon Moon 1 Kokushibo.
Although Michikatsu Tsugikini is not even introduced in the series, his fanbase is enormous because he is one of the strongest characters in the Demon Slayer series and the most powerful character in the series.
He is also a manga reader’s favourite character. This article will discuss his past, how Kokushibo became a demon, and why Kokushibo became a demon.
Let us read along to know the details.
Kokushibo’s Backstory: Who was Michikatsu Tsugikini? and what was his relationship with Yoricchi?
Kokushibo was one of the strongest Hashiras from the Sengoku Era.
The user of the Moon Breathing technique Kokushibo’s powers in Demon Slayer were only next to his brother Yoricchi, the creator of the Sun Breathing Technique from which the other breathing styles were created.
Kokushibo, aka Michikatsu Tsugikini, was born into a samurai family, and he had an elder brother named Yoricchi Tsugikini.
Yoricchi and Michikatsu’s mother were suffering from a disease, and from the beginning, it seemed Yoricchi was weaker.
His father, Akeno, chose Michikatsu as his successor, so he was trained by him, who was also considered one of the best masters in the country.
As Michikatsu started training with his dad, Yoricchi used to watch his younger brother practice from a distance.
One day, Michikatsu saw that Yoricchi was looking at his practice, so he gave him the sword and challenged him.
Surprisingly, Yoricchi defeated Michikatsu.
His father heard this news, and he chose Yoricchi as a successor.
Yoricchi always used deep breathing techniques while fighting, which he later developed and was known as the Sun Breathing, i.e. breathing of the sun (Hi no Kokyu)
Yoricchi was aware that his brother Michikatsu was passionate about sword fighting and loved to become a samurai.
As Yoricchi wanted to see his brother happy at any cost, Yoricchi sacrificed his dream for his brother and left home so Michikatsu could become the successor.
Later on, Michikatsu became a samurai and had a beautiful family.
But one day, when a demon attacked his house, Michikatsu could not defeat him, and his brother Yoricchi came to rescue him and his family. He saved his life and saved his family.

The whole incident humiliated Michikatsu, and he became jealous.
After that, Michikatsu joined Demon Slayer Corp to become as strong as his brother, but he couldn’t master the breathing of the sun (Hi no Kokyu) created by his brother, so he made a new form of breathing which was known as the moon breathing.
His breathing was not durable enough to surpass the strength of Yoricchi, so his greed to become strong grew daily.
How did Kokushibo become a Demon?
As Muzan was aware of Yoricchi’s powers, he wanted a partner to defeat Yorrichi.
On the other hand, Michikatsu was frustrated because he could not surpass Yoricchi, and he was also scared of the fact that most of the demon slayer mark users died after reaching the age of 25.
As a result, Muzan eventually persuaded Michikatsu to become a demon and be immortal. As Michikatsu wanted to be more powerful than Yoricchi, he agreed to become a powerful demon.
Therefore Muzan gave the most amount of blood to Michikatsu to turn him into a demon.
As Michikatsu was the user of the moon-breathing style, it took almost 3 days to transform into a demon fully.
Finally, after 3 days, Michikatsu became Kokushibo, aka the upper demon 1.


After this point, Muzan and Kokushibo started killing sun-breathing users from every era because they were the only threat to them.
Kokushibo’s Powers and Abilities Explained: What are the powers and abilities of Kokushibo?
Kokushibo is the only demon with blood demon art and mastered moon breathing.
His regeneration, speed and strength are near to Muzan.
He is so powerful that he can take down three strong hashira alone.
Kokushibo is most loyal to Muzan as he gave him most of his blood.
Mostly in fights, he doesn’t use blood demon art; instead of it, he uses his moon breathing, and the breathing is so powerful that it’s enough to kill any hashira if he or she is not the user of a powerful breathing style like Sun Breathing, Stone Breathing, etc.


Moon breathing has 16 forms.
He can see through the transparent world just as his brother Yoricchi used to do.
He has six eyes on his face, many eyes on his sword, and his katana is a blade with alternative blades that are terrifying to watch.
Kokushibo’s blood demon arts, such as Flesh Manipulation and Sword Manipulation, are very powerful.
His Flesh Manipulation technique can regenerate a Kantana-like sword from the detached part of his body, and also, at the same time, the detached parts get regenerated quickly because of his immense regeneration abilities.
Because of his infinite stamina and endurance, he can continue to fight with his full strength with any Hashiras at any given point.
Even Hashiras feared him because of his powers.
He also overpowered Sanemi Shinazugawa, Muichiro Tokito and Gyoemi Himejima when they awakened the demon slayer mark.
Why is Kokushibo the best character in the series?
I won’t say that he is the best character in the series, but before he died, he did agree that greed had taken over him all these years and whatever he had done was wrong, because of which some of the fans like Kokushibo.
When Himejima and Sanemi defeated Kokushibo, he felt sorry and guilty for what he had done.
He wanted to make all things right, but the time was gone.
He realized that he had left his beloved family, including his brother, wife, and children.
What and How Is the nature of Kokushibo?
Many fans will assume that Michikatsu Tsugikini, aka Kokushibo, is ruthless, which is to some extent correct because he got the most amount of blood from Muzan, because of which, to some extent, his and Muzan’s nature is somewhat alike and therefore he is ruthless when he fights his opponents.
Although he has committed many crimes, he is not as cruel as Muzan.
Though he felt jealous of Yoricchi, which later motivated him to become a demon, when Himejima and Sanemi defeated him, he agreed that he loved his brother very much and felt bad for betraying him.
He is a person who praises the Hashiras and also gives them the offer to become powerful demons and live for centuries.
But he does insult those who are weak.
Also, Kokushibo shows off the fact that the upper moon one and the right-hand man of Muzan.


I could never do good things in my life.
I betrayed my home.
I betrayed my beloved wife.
I betrayed my lovingly children.
I betrayed my father’s dream that they wanted me to be a great man and a great samurai who would protect every person in the country. I killed my descendants. But this was not enough for me.
You said that those who will perfect their ways would end at the same place. But I was not able to do it.
Why was I not able to do it? Why could I not become the person you and our family wanted me to become? Why are we both so different from each other?
Why couldn’t I become a worthy and good person for the world? Why was I born in this world in the first place?
Tell me…..Yoricchi
These were the final words of Kokushibo to Yoricchi.