One of the great things aboutDemon Slayeris the fact that almost every character has a backstory. From a cruel demon to a ruthless demon slayer, everybody in this series has a story to tell, most of which are quite tragic and surprising.
As the penultimate story arc that features quite a few major characters, both from the demons and the demon slayers’ sides,the Infinity Castle arcwill reveal numerous backstories that, once again, are quite tragic and surprising. So with that in mind, the following are every backstory that will appear in the Infinity Castle arc, ranked based on how interesting they are. Since this is a highly subjective list, feel free to disagree with the order of this list.
Kaigaku
A Disgruntled Demon Slayer
Kaigaku was a Thunder Breathing user, just like Zenitsu. In fact, he was actually a highly respected senior who had helped Zenitsu a lot during their training day. At the time, Zenitsu was considered a failure because he could only perform the first form ofthe Thunder Breathing Style: Thunderclap and Flash.Kaigaku, on the other hand, could perform every form of the Thunder Breathing Style, except the first one.
Unfortunately for Kaigaku, the first form is the foundation for the Thunder Breathing Style. That’s why their teacher, the former Thunder Hashira, chose Zenitsu as his successor, instead of Kaigaku. He was frustrated, but no matter how hard he tried, he couldn’t master the Thunderclap and Flash. In his moment of weakness, he accidentally met the Upper Rank One of the Twelve Kizuki, Kokushibo. The demon offered him power in exchange for his allegiance to Muzan Kibutsuji. Kaigaku accepted, and he became the new Upper Rank Six of the Twelve Kizuki.
Sanemi Shinazugawa
The Ruthless yet Gentle Hashira
Sanemi Shinazugawa is the Wind Hashiraand the older brother of Genya Shinazugawa. We already see a bit of his past through Genya’s recollection in the previous arc, but the Infinity Castle arc will dive deeper into what happened after Sanemi was forced to kill his mother, who was turned into a demon when they were young. After that terrible accident, Sanemi realised two important things. Firstly, he has a special blood called the “Marechi” that can attract and intoxicate demons. Secondly, to protect his little brothers and sisters from demons who might come for his blood, Sanemi had to leave his family behind.
Soon after, Sanemi met a demon slayer named Masachika Kumeno, who not only introduced Sanemi to join the Demon Slayer Corps, but also considered Sanemi to be like his own little brother. Unfortunately, Masachika would later lose his life to a vicious demon. Determined to continue Masachika’s legacy and to obtain more power so that he can protect his family from afar, Sanemi kept working hard until he eventually became the Wind Hashira.
Kokushibo
The Pitiful Life of the Greatest Demon Swordsman
When he was still a human,Kokushibo was known as Michikatsu Tsugikuni,the brother of the founder of the Demon Slayer Corps, Yoriichi Tsugikuni. Michikatsu was a remarkable swordsman, but he was no match for his genius brother, who managed to invent the Breathing Style sword technique. Even Muzan Kibutsuji, the progenitor of all Demons, nearly lost his life at the hands of Yoriichi.
No matter how hard Michikatsu trained his sword techniques, he knew that he wouldn’t be able to surpass his brother. He couldn’t bear the thought of losing to his own brother, so he sought other ways to gain power. That’s when he met Muzan. The Demon Lord offered him boundless power and an eternity to hone his swordsmanship. In his desperation, Michikatsu agreed. And thus, a demon named Kokushibo was born.
Doma
A Cruel and Privileged Demon
Ever since he was born, Doma has enjoyed a life full of luxury and privileges as the leader of the Paradise Faith Religion, also known as the Eternal Paradise Faith. His charming appearance lured innocent and naive people to admire and even worship him. But having been in the position of the leader of a fanatic cult since he was small, Doma ended up looking down on humanity and developed a psychopathic tendency.
Things took a turn for the worse when he met Muzan Kibutsuji. Doma didn’t really have any attachment to living as a human at that point, so when Muzan offered her the chance to become a being that far surpasses humanity, he gladly accepted it. From that point on, Doma lived like the god that he had been pretending all this time. With his newfound power, he took great pleasure in performing impossible miracles for his loyal followers, only to consume them afterward. Thus began the life ofthe cruelest and most psychotic demon in history.
Inosuke
The Heartbreaking Past of the Wild Beast
Many people think thatInosuke was abandoned by his parentsin the woods when he was little. But the truth was actually a lot more complicated than that. Inosuke’s mother was a beautiful young woman named Kotoha. Unfortunately, his husband abused her physically and mentally to the point that she had to seek refuge in a well-known religious cult called the Eternal Paradise Faith. Little did she know that it was actually the lair of a cruel demon named Doma.
Interestingly enough, Doma was captivated by Kotoha’s beauty and amused by her cheerfulness. That’s why he intended to keep her around. But it didn’t take long for Kotoha to realize that Doma actually a demon and he regularly consumed the flesh of his followers. Kotoha tried to run away, but to no avail. In front of her was a steep cliff, and behind her was the fast-approaching Doma. In her desperation, she threw baby Inosuke into the river, hoping that her beloved son would survive somehow. As Kotoha saw her baby taken away by the stream, she felt Doma’s cold hand pierce her heart.
Shinobu Kocho
A Vengeful Hashira
One of the reasons why Shinobu decided to become a demon slayer and work as hard as she can to achieve the rank of Hashira is to avenge her parents and her beloved older sister. Her parents were killed by a demon when they were young, but thanks to Gyomei Himejima, the sisters survived and entered the Demon Slayer Corps.
The older sister, Kanae Kocho, eventually becomes the Flower Hashira. But even she inevitably lost her life to a high-ranking demon named Doma. From that point on, Shinobu honed her skills and her knowledge in order to find a way to slay the demon who killed her sister. She has vanquished many demons asthe Insect Hashira,but her ultimate goal remains the same. To kill Upper Rank Two of the Twelve Kizuki: Doma.
Akaza
The Tragic Life of a Battle-Crazed Demon
When he was still a human, hundreds of years ago, Akaza went by the name of Hakuji. He came from a poor family, but he had a kind heart and was blessed with a strong body. Unfortunately for him, nobody was willing to give him a chance, so he ended up having to resort to stealing and pickpocketing, which usually led to a brawl. He won, of course. He would come home with bruises, but his opponent always ended up with broken bones and critical injuries.
Not long after his father passed away, Hakuji met Keizo, a martial arts instructor. Keizo lived alone with his daughter in a rundown dojo.They may be poor, but they were happy.There, Hakuji not only learned about martial arts, but Keizo also taught him discipline and respect. It didn’t take long before he fell in love with Keizo’s daughter. For once in his life, he was happy. But those happy days didn’t last long.
Right before his wedding day, somebody poisoned the dojo’s well, killing Keizo and his daughter. Enraged, Akaza went on a killing spree. He hunted everybody whom he deemed their enemies and massacred them with his bare hands. The harder he fought, the more he damaged his body, and the more he craved strength. That’s when he met Muzan, who offered him unlimited power as a demon. Hakuji accepted. And that’s how the demon known as Akaza was born.
