fostered a drive to become as strong or surpass his brother, a sentiment so strong that he abandoned his family to pursue becoming a Demon Slayer.completely surpassing the curse of the Demon Slayer Marks that killed anyone that awakened them before they turned 25 However, despite this immense jealousy, spite, and outright hatred he harbors for Yoriichi, he still deeply cares for his brother Frustrated from being unable to surpass.his.Michikatsu was persuaded by Muzan Kibutsuji to become a demon, taking the name Kokushibo.in his demon form possesses long, spiky black hair with red tips, that he keeps in a ponytail. His most notable feature is the three sets of eyes on his face with yellow irises and red flesh sclera that have black straight lines diverging from each iris. His middle set of eyes has the kanji of "Upper Rank." on engraved on his left eye, and daiji for "One" on his right.As a human, Kokushibo/Michikatsu look was almost identical to his demon form, except for the number of eyes, his eminent eyebrows, and his less light skin. His eyes had dim purple irises and normal, white sclera as a human. He also tied his hair in a short ponytail, unlike Yoriichi who wore his loose.One day, when yoriichi saw his older brother, he realized that he was a demon. Yoriichi accepted his brother but even though he was a demon After all, he couldn't kill his brother, he couldn't do that... he was still his older brother so he put a bamboo muzzle in his mouth and This may prevent him from speaking, but it will suppress his desire and urge to eat. But now that he has the bamboo in his mouth.sensing that Yoriichi had come home,but muffle the sound of the bamboo muzzle in his mouth.

Kokushibo/Michikatsu: "mmmph!"

And yoriichi knew that demons' weakness was the sun and since his older brother was a demon he had a weakness to the sun and sunlight was deadly to him so he went to his mission in the morning He would carry it with the wooden box on his back and go to the mission.Also, when yoriichi went on missions, it was as if his younger brother, Yoriichi,He had just come home from mission And put the box on the floor had closed the curtain just to avoid being burned his own brother by the sun. He could see this by looking at the closed window, how jealous he was of his little brother's sun breath technique And even though he felt hatred and resentment, he still had love and affection for Yoriichi.Meanwhile, yoriichi also knew why his brother transformed into sun breath and was jealous of him because he had opened the demon slayer mark before he was twenty-five, and because his older brother was jealous, he became a demon He accepted to be with the offer given by Muzan Kibutsuji. Yoriichi turned his attention away from the sun, and my gaze fell on the wooden box that yoriichi had placed on the floor after returning from his own mission. He let out a gentle sigh, and then began to approach the box. Once yoriichi reached it, he slowly knelt down, being careful.yoriichi reached out his hand toward the lid of the box, his touch gentle and slow.yoriichi carefully lifted the lid up, slowly, the sound of the wood creaking under his touch being the only thing heard in the room. Once the lid was lifted completely, yoriichi red eyes gaze was met with the familiar figure inside. Kokushibo, the older brother yoriichi once knew.