Yoriichi didn't let Muzan live intentionally, but failed to kill him because Muzan's body shattered into many pieces (around 1800), and Yoriichi, despite his immense power, couldn't destroy all of them before Muzan regenerated, giving him the chance to escape. Yoriichi was caught off guard by Muzan's desperate self-destruction and his own inability to comprehend such a brutal escape, questioning Muzan's humanity just as he was about to deliver the final blow, allowing Muzan time to flee as a smaller fragment.
He meets Sumiyoshi, sat down with him, and told him his entire story, from his beginning to his banishment from the Demon Slayers. Reminded of his tragedies and speaking of his regret at letting Muzan live and the countless death that would follow, Yoriichi grew despondent.
The 'touching points' you mentioned are some of the reasons why people find Kokushibo's story to be sad. Because while Kokushibo was envious and held resentment towards Yoriichi, he still loved his brother. He kept the flute for a reason, and it wasn't out of jealously. And the realization at the end of his life?
Muzan has always been a rational character, but fans believe killing his doctor is the only time he regretted taking a life.
Kit Cat Marzyy Muzan's fear of Yoriichi is based on his fear of Death. Yoriichi was the one who came closest to killing him and that's his fear. MUZAN even run away from Obanai and Tanjiro because he was afraid of dying not because he isn't stronger than them. But because the situation wasn't in his favour.
Also the reason why Nezuko was already so powerful is because Muzan injected tons of blood in her body and the others in hopes of creating a demon that could conquer the sun.
Seeing his chance, Yoriichi perfected his Sun Breathing technique forms and combines them into a single attack, creating the Thirteenth Form and final form of Sun Breathing. With it, he cuts through all of Muzan's vital organs and overpowers Muzan completely.
Muzan was dead, almost all demons died with him. Yushiro is the only one who survived, he's a good demon tho. He was free from Muzan, that's why he was okay. Demon Slayer Corps were disbanded after the fight...
He is the 50th Pure Evil to be headlined. His counterpart in Demon Slayer Academy doesn't count as a PE because he has too many comedic moments.
Tanjiro is not a Hashira within the Demon Slayer Corps. Officially, the highest rank he attains is Hinoe, the third highest position within the Corps.
The only canonically LGBTQ+ character in Demon Slayer is Suma, one of Tengen Uzui's wives, who is confirmed to be bisexual and polyamorous in the series' databooks, showing affection for both men and women, including Tengen and her fellow wives, Makio and Hinatsuru. While other characters like Mitsuri are speculated to be queer, Suma is the sole officially confirmed character, with her relationship dynamic highlighting both bisexuality and polyamory within the Demon Slayer Corps.
While many Hashira died in the fight, some survived: Giyu Tomioka, the Water Hashira, and Sanemi Shinazugawa, the Wind Hashira, both survive the final fight, carrying on the memory of their fallen comrades. Tanjiro also survives, and after the war, the Demon Slayer Corps disbands because demons are gone for good.
Swordsmith Village Arc
After falling into a coma in the aftermath of his battle against Upper Rank Six, Tanjiro Kamado dreams of memories belonging to his ancestor Sumiyoshi. Within them, Yoriichi is seen holding a newborn Sumire as her mother sleeps.
Even 400 years later, Muzan's fear of Yoriichi remained fully intact, as simply laying eyes on Tanjiro's hanafuda earrings caused him to recall their clash.
Yoriichi cuts a little over 1500 pieces of Muzan.
He can defeat them all in 1 blink as you see all uppermoon is feared on muzan presence but muzan afraid on yoriichi himself so he can prob wipe them all up.
Demon Slayer enthusiasts are buzzing about the connection between Tanjiro Kamado and the formidable Upper Moon One, Kokushibo. While not directly related, Tanjiro is seen as the spiritual successor to Yoriichi Tsugikuni, Kokushibo's twin.
After accidentally consuming a drug created by Tamayo, Yushiro, and Shinobu that was deliberately designed to counter his abilities and weaken him over time, Muzan's hair grows in length and turns white due to the drug drastically accelerating his biological age.
Muzan Kibutsuji: The ultimate unkillable demon king
Muzan's real scary gimmick isn't his power, but the fact that he can't die from a head cut-off. Even when the most powerful Hashira—Gyomei Himejima—does succeed in beheading him, Muzan absurdly regrows his head in an instant.
By the end of the manga, only one Hashira survives and lives a full life: Tengen Uzui, the Sound Hashira. The rest meet tragic ends, either in battle or due to the toll of their Demon Slayer Marks.
One of the reasons people might consider Shinobu the "weakest" Hashira is because, unlike the others, she can't behead demons, which is usually the easiest way to kill them. Instead, she uses poison to defeat them.
✅Breathing technique Yoriichi created the breathing technique known as Sun Breathing, which he modified to teach to other Demon Slayers. The variations he created became the Water, Wind, Flame, Stone, and Thunder Breathing techniques.
Though Gojo is arguably stronger and would likely win in a fight with Yoriichi, Yoriichi embodies the concept of being "the strongest" better.
Ten years after they first met, the two got married. The final month of Uta's pregnancy approached, Yoriichi had to leave her at home as he went to fetch a midwife, however upon returning he found that his wife and unborn child had both been slaughtered in cold blood by a Demon.