Demon Slayer: Every Backstory That Will Appear in Infinity Castle Arc, Ranked

Among the many appealing aspects of “Demon Slayer” is its rich character development, as nearly all characters possess their own captivating backstory. Ranging from tormented demons to relentless demon slayers, each figure in this series carries a tale worth sharing, often filled with heart-wrenching and unanticipated twists.

Previewing the penultimate storyline brimming with key characters from both demon and slayer factions, the Infinity Castle saga will unveil numerous heart-wrenching and captivating backstories. Here’s a rundown of every backstory you can expect in the Infinity Castle arc, arranged according to their intrigue factor. Keep in mind that this list is subjective, so feel free to share your thoughts on the order!

This paraphrase aims to make the original text more readable and engaging while maintaining the same information and tone.

Spoiler Alert!

Kaigaku

A Disgruntled Demon Slayer

First Appearance: Tomokazu Sugita
Japanese VA: Yoshimasa Hosoya

As an ardent admirer, let me share a fascinating tidbit about Kaigaku, who, much like Zenitsu, wielded the mighty Thunder Breathing technique. However, unlike Zenitsu, Kaigaku was a revered elder, a mentor who significantly aided Zenitsu in our shared journey of growth. During those formative days, Zenitsu was seen as a disappointment, his abilities limited to the initial form of Thunder Breathing: Thunderclap and Flash. In stark contrast, Kaigaku excelled beyond the first form, mastering every subsequent aspect of the Thunder Breathing Style, save for the very first one.

Unfortunately for Kaigaku, it was the initial shape that formed the basis for the Thunder Breathing Style. Consequently, his teacher, the former Thunder Hashira, opted to pass on this role to Zenitsu rather than Kaigaku. This left Kaigaku feeling disheartened as he struggled to master the Thunderclap and Flash techniques. In a moment of despair, Kaigaku encountered the Upper Rank One of the Twelve Kizuki, Kokushibo. The demon sensed his vulnerability and offered him power in exchange for loyalty to Muzan Kibutsuji. In a weakened state, Kaigaku agreed, thus ascending to the position of new Upper Rank Six within the Twelve Kizuki.

Sanemi Shinazugawa

The Ruthless yet Gentle Hashira

First Appearance: Episode 22
Japanese VA: Tomokazu Seki

In the upcoming Infinity Castle arc, we’ll delve more into the life of Sanemi Shinazugawa, the Wind Hashira, following the tragic event where he was compelled to slay his demon-transformed mother when they were young. After this traumatic incident, Sanemi discovered two crucial truths. Initially, he learned that he possesses a unique bloodline called “Marechi,” which draws and enchants demons. Secondly, to safeguard his younger siblings from potential threats seeking his special blood, Sanemi was forced to part ways with his family.

Shortly thereafter, Sanemi encountered a Demon Slayer named Masachika Kumeno. Not only did Masachika invite Sanemi to join the Demon Slayer Corps, but he also regarded Sanemi as his younger brother. Tragically, Masachika perished at the hands of a ferocious demon. Eager to honor Masachika’s memory and strengthen himself for the purpose of shielding his family from afar, Sanemi persevered in his efforts until he eventually ascended to the rank of Wind Hashira.

Kokushibo

The Pitiful Life of the Greatest Demon Swordsman

First Appearance: Episode 45
Japanese VA: Ryōtarō Okiayu

As a human, Kokushibo went by the name Michikatsu Tsugikuni and was the brother of Yoriichi Tsugikuni, the founder of the Demon Slayer Corps. Michikatsu was an exceptional swordsman, but he couldn’t keep up with his incredibly gifted sibling who developed the Breathing Style sword technique. Even Muzan Kibutsuji, the ancestor of all demons, came close to meeting his end at Yoriichi’s hands.

Regardless of how intensely Michikatsu honed his martial arts skills with the sword, he accepted that he wouldn’t outdo his brother. The idea of losing to his own sibling was too much for him, so he looked for alternative means to amass strength. It was then that he encountered Muzan, the Demon Lord, who promised him limitless power and endless time to perfect his swordplay. Overwhelmed by his predicament, Michikatsu consented. Consequently, a demon known as Kokushibo emerged from this deal.

Doma

A Cruel and Privileged Demon

First Appearance: Episode 45
Japanese VA: Mamoru Miyano

From his birth, Doma has led a life of opulence and special privileges as the head of the Paradise Faith Religion, or Eternal Paradise Faith. His attractive features attracted admiration and even reverence from unsuspecting and gullible individuals. However, due to being in charge of a fanatical cult since his youth, Doma eventually developed a disdain for humanity and exhibited signs of psychopathic behavior.

I found myself witnessing a pivotal moment when he crossed paths with Muzan Kibutsuji. Doma, weary of human existence, grasped the opportunity Muzan presented – transcending humanity to something superior. From then on, he embraced his role as the deity he had long feigned. His newfound prowess allowed him to astound followers with miracles beyond belief, yet these acts were merely a prelude to his insidious consumption. And so, the life of history’s most ruthless and psychotic demon unfolded.

Inosuke

The Heartbreaking Past of the Wild Beast

First Appearance: Episode 11
Japanese VA: Yoshitsugu Matsuoka

It’s widely believed that Inosuke was left alone in the forest as a child by his parents. However, the real story is much more intricate. Inosuke’s mother, a woman named Kotoha, was indeed beautiful but endured severe physical and emotional abuse at the hands of her husband. To escape this torment, she sought sanctuary within the Eternal Paradise Faith, a well-known religious group. Unbeknownst to her, this group was actually the stronghold of a wicked demon named Doma.

It’s intriguing to note that Doma found Kotoha both beautiful and amusing, which led him to want to keep her near. However, it didn’t take long for Kotoha to discover that Doma was a demon who fed on the flesh of his followers. Desperate to escape, Kotoha found herself trapped with no way out – a towering cliff behind her and Doma quickly closing in. In her frantic attempt to save herself, she tossed baby Inosuke into the river, hoping against hope that he would make it. As Kotoha watched her child being carried away by the current, she felt Doma’s icy touch pierce her heart.

Shinobu Kocho

A Vengeful Hashira

First Appearance: Episode 15
Japanese VA: Saori Hayami

One reason Shinobu chose her path as a demon slayer and strives tirelessly to reach the rank of Hashira is her desire for vengeance – avenging her parents who were cruelly taken by a demon in their youth, and her cherished elder sister. Fortunately, Gyomei Himejima intervened, ensuring that Shinobu and her sister survived, eventually joining the Demon Slayer Corps.

As an observer, I witnessed the progression where Kanae Kocho, the elder sibling, ascended to the position of Flower Hashira. Regrettably, she fell to a formidable demon known as Doma, leaving behind her life. From that fateful moment onward, Shinobu dedicated herself to enhancing her abilities and gaining knowledge in an attempt to devise a strategy to vanquish the demon responsible for her sister’s demise. She has defeated countless other demons, standing strong as the Insect Hashira. However, her ultimate objective continues to be relentless – to eliminate Upper Rank Two of the Twelve Kizuki: Doma.

Akaza

The Tragic Life of a Battle-Crazed Demon

First Appearance: Kimetsu no Yaiba: The Movie – Mugen Train
Japanese VA: Akira Ishida

In his past life, several centuries ago, Akaza was recognized as Hakuji. Born into poverty, he possessed a compassionate spirit and a robust physique. Regrettably, opportunities eluded him, forcing him into petty theft and pickpocketing, which often sparked fights. As fate would have it, he always emerged victorious from these encounters. Despite returning home battered, his opponents incurred more severe injuries, including fractures and critical wounds.

Following the demise of his father, Hakuji encountered Keizo, a martial arts master who resided secludedly with his daughter in a dilapidated dojo. Despite their poverty, they found contentment. It was here that Hakuji not only absorbed martial arts knowledge but also learned values such as discipline and respect from Keizo. In no time at all, he developed feelings for Keizo’s daughter. For the first time in his life, he knew true happiness. Unfortunately, this period of joy didn’t endure long.

Just before his wedding day, someone contaminated the dojo’s well, causing the death of Keizo and his daughter. Overwhelmed with anger, Akaza embarked on a rampage. He sought out and brutally murdered anyone he considered an enemy using only his bare hands. The more he fought, the worse he injured himself and the stronger his desire for power grew. It was then that he encountered Muzan, who granted him infinite power in exchange for becoming a demon. And thus, the demon known as Akaza came to be.

2025-08-02 00:36