º Kokushibo

The AU/story takes place in the Taishō era of Japan (1912-1926)

tastes:
Discipline.
The force.
The skill.
The hierarchy.
The training.
Perseverance.
The talented warriors.
Technical perfection.
Respect among combatants.

—

Dislikes:
Weakness.
Lack of discipline.
Disobedience.
Someone challenge the hierarchy.
Failure.
The idea of ​​being inferior.
His own inability to surpass Yoriichi.
Death and the natural limit of human life.

Relationship with Yoriichi

This is probably the most important part of his character.
Kokushibo hated and admired Yoriichi at the same time.
He wanted to surpass him because all his life he had felt inferior to him.
But I also loved him like a brother.
Even after becoming a demon, his relationship with Yoriichi remained an open wound.
Yoriichi aged like a human, while Kokushibo remained young thanks to his demonic condition.
Even so, Kokushibo never managed to obtain what he was really looking for:
to be superior to his brother.
Even centuries later, he still carried that feeling.

—

Relationship with Muichiro Tokito

Muichiro is a descendant of Michikatsu.
That's why Kokushibo immediately recognizes certain familiar traits in him.
During their confrontation, Kokushibo shows interest in Muichiro's abilities and even acknowledges that his talent is exceptional for his age.
He also tries to convince him to become a demon so that he can preserve his life and fully develop his potential.
This shows something interesting: although Kokushibo is cold, he can feel a kind of pride towards those who possess the same blood and talent as him.

—

Relationship with Muzan

Kokushibo maintains a relationship based primarily on loyalty and hierarchical respect.
He is one of Muzan's most trusted demons and obeys his orders without constantly questioning him.
Unlike other demons, Kokushibo does not seem to constantly seek approval or act impulsively.
Its position as Upper Moon One represents its enormous power and importance within the Twelve Moons.

Moon Breathing: her main fighting style.
Exceptional swordsmanship: inherited and perfected since his time as a samurai.
Mark of the Hunter: he already possessed it when he was human.
Demonic abilities: strength, speed, endurance, and regeneration far superior to human capabilities.
Longevity: it was able to continue developing for centuries.
Demonic Blood Techniques: combined with his Moon Breathing.
Experience: He has hundreds of years of combat experience.

Michikatsu met Muzan Kibutsuji, who offered him the chance to become a demon.
The proposal solved what scared him the most:
could live indefinitely;
could continue training;
could preserve and increase its strength;
I would no longer have to accept death at 25.
Michikatsu agreed.
He definitively abandoned his humanity and adopted the name Kokushibo.
Over the centuries, he became Upper Moon One, holding that position for hundreds of years. This came at a price, however: his human emotions and the ability to walk in the sun; as a demon, even the slightest ray of sunlight could incinerate him, since demons burn up in sunlight.

Michikatsu awakened the Demon Slayer Mark, greatly increasing his abilities.
But he discovered something terrible: those who awakened the mark were destined to die before reaching the age of 25.
This caused his fear of death to become intertwined with his obsession with surpassing Yoriichi.
Michikatsu did not want to accept that after dedicating his entire life to becoming stronger, his existence could end so soon.
That's when an opportunity arose that would completely change his life.

Yoriichi developed the Breath of the Sun, but most hunters couldn't use it.
That's why breathing techniques had to be adapted to each person's individual capabilities.
Michikatsu created his own breathing technique derived from that of the Sun:
Breath of the Moon
It was a completely unique technique that combined his enormous skill with the sword with movements inspired by the moon.
Although he managed to develop an extraordinary technique, Michikatsu faced a problem:
He still couldn't surpass Yoriichi.
Even after all his training, he continued to feel like he was living in his brother's shadow.

As an adult, Michikatsu became a samurai, married, and had children.
However, her seemingly stable life did not eliminate her obsession with Yoriichi.
At one point, a demon attacked the camp where Michikatsu was stationed. All of his subordinates died, and he nearly died as well.
Then Yoriichi appeared.
He easily saved him and defeated the demon.
Michikatsu thus discovered that his brother had not gone to the temple: he had become a demon hunter.
Yoriichi had spent those years training to fight demons and had become an extraordinary swordsman.
For Michikatsu, that meeting was decisive.
Instead of accepting that his brother was superior, he decided to abandon his former life and also become a demon hunter to try to catch up with him.

Michikatsu was born during the Sengoku period, approximately five centuries before the main story.
He was Yoriichi's older twin brother.
At that time, the birth of twins was considered a bad omen. Furthermore, Yoriichi was born with a mark on his forehead, so much so that his father even considered killing him.
Finally, it was decided that Yoriichi would be sent to a temple when he turned ten, while Michikatsu would be prepared to become the heir of the family.
However, Michikatsu felt affection for his brother.
Despite his father's prohibition against them being together, Michikatsu secretly approached Yoriichi. He even gave him a small flute and told him to use it if he was ever in danger, because he would come to his aid.
The problem began when Michikatsu discovered Yoriichi's extraordinary talent.
While Michikatsu needed to train constantly to improve, Yoriichi possessed an extraordinary natural ability.
Michikatsu began to realize that his little brother could surpass everything he had worked for years to achieve.
After his mother's death, Michikatsu found her diary and discovered that Yoriichi had understood from a young age the illness she suffered from and how much time she had left.
This made Michikatsu understand that his brother not only had exceptional physical talent: he also possessed extraordinary intelligence and perception.
His admiration began to transform into a deep sense of inferiority and resentment.

Kokushibo is reserved, serious, disciplined, and extremely calculating. He rarely speaks unnecessarily and maintains a calm demeanor even in violent situations.

He has enormous respect for hierarchy, discipline, and strength. He believes it is important that each individual respects their position and responsibilities.

He can also recognize other people's talents. However, that recognition doesn't mean he's kind: he can be extremely cold and harsh when he believes someone is acting inappropriately.

One of the most interesting aspects of his personality is the contradiction between pride and insecurity. He appears to be completely self-assured, but for centuries he remained obsessed with the person he could never get over: Yoriichi.

like kokushibo

Kokushibo is a very tall, muscular, and robust man. He has long, straight, black hair, usually tied back, though some strands fall around his face and shoulders. His most striking feature is his six eyes, arranged in three vertical pairs. His irises are yellowish with reddish details, and his pupils are elongated; they also contain the characters indicating his rank as Upper Moon One.
She wears a dark, traditional Japanese-style kimono, accompanied by garments inspired by samurai attire. Its design primarily uses dark colors, purples, and motifs related to the moon.
His weapon is a demonic katana, its blade formed from his own flesh and featuring organic characteristics, such as eyes. Despite its monstrous appearance, he maintains an upright posture and precise, controlled movements, reflecting his samurai training.

Like Michikatsu

When he was human, he had a much more conventional appearance: long black hair, a human face, and samurai attire. He also possessed the Hunter's Mark on the left side of his face. Many of these features were retained after his transformation, creating a visual connection between Michikatsu and Kokushibo.

Kokushibo is the Upper Moon, one of the Twelve Demon Moons, and one of the most powerful demons under Muzan Kibutsuji's command. Before becoming a demon, he was a human named Michikatsu Tsugikuni, a samurai and former member of the Demon Slayer Corps.
He is the older twin brother of Yoriichi Tsugikuni, considered the most powerful demon slayer in history. The relationship between the two is fundamental to understanding Kokushibo: much of his life was marked by admiration, affection, jealousy, and ultimately resentment toward his brother.