Four Demon Slayers who are more powerful than Kokushibo.
Kokushibo is the Upper of Level 1, but Muzan, Yoriichi, Gyomei Himejima and Tanjiro are stronger than him through inheritance or combat effects.
In Demon Slayer, Kokushibo takes the place of Upper Rank One, the strongest amongst the twelve Kizuki, and he is also the second most powerful demon after a main villain named Muzan Kibutsuji. He was previously Michikatsu Tsugikuni, an extremely powerful demon slayer whose attributes include Moon Breathing, Transparent World, and upgrades bestowed by the Demon Slay Mark. There are few characters more powerful than him, be they gods or humans.
Muzan Kibutsuji is the ceiling of the Demon King.
The series' main antagonist, Muzan Kibutsuji, is one of the best demons in existence. He has been around for over two thousand years and is an ancestor to all demons, so his strength, speed, and endurance in combat far surpasses that of 12 Kizuki and the Demon Slayer Corps.
Yoriichi Tsugikuni is the face of humanity.
Before becoming a demon, Kokushibo was Yoriichi Tsugikuni's twin brother Michikatsu Tsujikuni and the greatest Demon Slayer of all time. Upper Rank One embraced Muzan's transformation out of jealousy for his immense power and effortless talent. Although Yoriki is absent from the current timeline, in the series he is considered to be the most powerful character in Demon Slay, and his legacy lives on.
A tribute to the 300th anniversary of Gomi Himejima commemorates the summit of Mount Hashira.
Gyomei Himejima is the Stone Hashira, and although unable to surpass Yoriichi, he is still the strongest Hashira within the Demon Slayer Corps. Koyoharu Gotouge, author of Demon Slayers confirmed that Gyomey's physical strength was the highest in the Corps; he possessed unnatural muscles and tight organs, and suffered from blindness. During a battle with Kokushibo, an evil demon claimed that Gyeomei was the best warrior she had faced for 300 years.
Tanjiro Kamado becomes the final uploader to become Tanger, the demon king.
Tanjiro's rise has led him into some of the most difficult battles in a short time. With help, he defeats Hantengu, Daki, Gyutaro, and Akaza. For starters, these abilities are equal to those of certain Hashiras and even greater than their weakest counterparts. He awakens his Demon Slayer Mark before many of them and unleashes Transparent World and Selfless State.
Why do ratings matter to readers?
Demon Slayer: Kimetsu no Yaiba features Natsuki Hanae as Tanjiro Kamado (vocals) and Akari Kito as Nezuko Kamado. The scenes were praised by Ufotable. For readers, Kōshibo is not the strongest of Kizuki's twelve; he holds the record for unveiling the series' power level.