Yoriichi and his older twin brother, Michikatsu, were born into the Tsugikuni clan within the middle of the Sengoku period, a time when twins were considered to be an extremely bad omen.
The flashback also reveals that Yoriichi had a twin brother named Michikatsu Tsugikuni, who became a Demon Slayer but later turned into a demon and became Upper Moon One, Kokushibo.
Many Kimetsu no Yaiba fans deduce that Yoriichi is Tanjiro's father, but that isn't the case. However, Yoriichi is responsible for teaching Tanjiro's ancestors the Hinokami Kagura, which has been passed down for generations.
However, Tanjiro is not a descendant of Yoriichi Tsukiguni. Tanjiro is the descendant of someone who knew Yoriichi personally and was a good friend of his as well. Sumiyoshi was rescued by Yoriichi when a demon threatened his life. Since then Yoriichi often met him and they became close acquaintances.
Yoriichi was the identical younger twin of Kokushibo — Michikatsu in this case since this is the name that Yoriichi knew him as. During their childhood, Michikatsu always looked at Yoriichi as inferior to him.
However, despite this immense jealousy, spite, and the outright hatred he harbors for Yoriichi, he still deeply cares for his brother, as seen when he was touched by Yoriichi treasuring the handmade flute he had made for him as children; Kokushibo sheds tears over his brother's death, and even goes as far as keeping ...
We first see Doma when he is still the Upper Moon Six while he is in the middle of eating a geisha. Later he becomes even stronger and rises to the position of Upper Moon Two. He dies because of the lethal amount of poison he absorbed through Shinobu Kocho's body followed by Kanao Tsuyuri beheading him.
As the battle reached its climax, Tanjiro was able to knock the doll's head off and discovered that the mechanical body contained a mysterious sword. Fans of the manga will recognize this sword as the one carried by Yoriichi Tsugikuni himself.
Is upper rank one Tanjiro's father? No, they are not related. Tanjiro, by PURE COINCIDENCE, heavily resembles Yoriichi Tsugikuni, the creator of Breath swordsmanship, the only other person to use Sun Breathing, and the only person Muzan ever feared.
But if we are talking about the human form, then it's a big fat NO, because Tanjiro has just mastered the Sun Breathing whereas Yoriichi is the inventor of it, also he's way more powerful and holds an unfathomable battle intellect, larger than any Demon Slayer in history, so in conclusion, no one is remotely close to ...
Tanjuro Kamado a recurring flashback hero from Demon Slayer : Kimetsu No Yaiba. He was the husband of Kie Kamado, and the father of Tanjiro, Nezuko, Takeo, Hanako, Shigeru, and Rokuta. Tanjuro was a flame dancer who used to dance the Hinokami Kagura during the winter.
Tanjiro's ancestor was a good friend of Yoriichi and arguably was one of his only true friends. Therefore Yoriichi gave the earrings as a gift, and since then they have been passed down the generations until they reached Tanjiro.
Tanjiro wasn't born with this scar on his forehead. Rather, he acquired it when tackling his younger brother out of the way of a falling pot of boiling tea. At the beginning of Demon Slayer, the scar was a light-pink, circular mark.
Devastated at what his brother had become, he cried, and Kokushibo could only show disgust that his younger brother was old but still alive despite having the mark. Yoriichi felt sorry for him, but knew he had to kill him and prepared to strike.
Yoriichi's wife, Uta, was killed by a demon while pregnant with their first child. Yoriichi devoted his life to slaying Demons and ultimately sought to kill Muzan Kibutsuji and Kokushibo.
Yoriichi lived until around 85 years, so: 1432 + 85 = 1517, exactly 400 years prior to when Kokushibo remembered and died.
The warrior Muzan feared was a swordsman named Yoriichi Tsugikuni. Yoriichi was the only slayer before Tanjiro who came close to killing Muzan, and the flashback of their fight occurred in Chapter 187.
Tanjiro is considered to be Muzan's main nemesis throughout the series. After murdering the Kamado family, he was personally sought out by Tanjiro in Asakusa, Tokyo when the Demon Slayer recognized his scent from the scene of the murder.
Kokushibo was the final Upper-Rank to die during Demon Slayer's "Infinity Castle" arc. Muichiro, Genya, Sanemi Shinazugawa and Gyomei Himejima fought together against Kokushibo, though Muichiro and Genya were no match for him and were killed.
The sword is primarily black, but it turns crimson red when the Breath of the Sun God (strongest breathing style) is used by both Tanjiro as well as Yoriichi.
So now, Tanjiro, the protagonist of the Demon Slayer series, has access to a sword that belonged to the best swordsman to have ever lived. This sword was in bad condition, but Hotaru Haganezuka took it upon himself to restore the blade to its former glory.
How Doma became the worst demon in Demon Slayer. Almost every creature possesses emotions, be it anguish, sorrow, happiness, or even fear. However, in the case of Doma, he doesn't feel a thing. During his childhood, his mother stabbed his father to death for cheating on her and, later on, took her own life.
In a nutshell, Muzan, being the progenitor of demons, is not scared of Doma. However, he is irritated by his inability to decipher Doma's thoughts and feelings, which is the ultimate control he has over all of his creations. Upper-Rank Two: Doma is a nihilistic maniac and a misanthropic cold-blooded demon.