10 unsolved Demon Slayer mysteries from the Hashira training arc

Demon Slayer mysteries abound in the Hashira Training Arc, particularly in its gripping finale. This pivotal storyline follows Tanjiro, Zenitsu, and Inosuke as they undergo grueling training under the Hashira at the Butterfly Mansion. The arc's conclusion showcases Tanjiro's desperate struggle to complete the final test – splitting the boulder.

Moments like Zenistsu's cold demeanor and Nakime's cameo raise intriguing questions. From unexplained abilities to the cryptic foreshadowing in Tanjiro's dream sequence, these unresolved Demon Slayer mysteries keep fans speculating.

In this article, we'll explore ten perplexing Demon Slayer mysteries from the Hashira Training Arc, delving into the enigmas that continue to fascinate Demon Slayer enthusiasts.

Disclaimer: This article reflects the writer's opinion.

Origin of demons, Founder of Demon Slayer Corps, and others are among unsolved Demon Slayer mysteries

1. Origin of Demons

Upper Ranks of the Twelve Kizuki (Image via Ufotable)

The creation of demons is rooted in a dark, unknown past. Muzan Kibutsuji, the first demon, was transformed by a mysterious doctor who sought to cure his illness using the Blue Spider Lily. However, the knowledge required to turn Muzan into a demon implies prior experimentation or ancient wisdom about demonic transformation.

This raises the question: were there demons before Muzan? The doctor's understanding of demonic abilities and the Blue Spider Lily suggests a hidden history of demon creation. Unraveling this origin could reveal more about Muzan's powers and the ancient practices that led to the existence of demons and will solve one of the most anticipated Demon Slayer mysteries.

2. How does Nezuko survive sunlight?

Nezuko surviving sunlight (Image via Ufotable)

Nezuko Kamado, unlike other demons, possesses a unique ability: she can withstand sunlight exposure, which stands as the plot's turning point. This remarkable trait was first revealed during the intense battle against the Upper Moon demons. While most demons burn to ashes under the sun's rays, Nezuko’s survival raises significant questions about her origins and potential.

Her resilience suggests a unique mutation or an unexplored aspect of Muzan’s blood that grants her this extraordinary ability. Nezuko's survival in sunlight is pivotal, as it hints at a potential vulnerability in Muzan's creations, making it one of the intriguing Demon Slayer mysteries.

3. Founder of Demon Slayer Corps

Members of Demon Slayer Corps (Image via Ufotable)

The background of Demon Slayer Corps, a group whose primary duties are to exterminate demons, has many secrets. The Corps has been active for as long as centuries, with its primary purpose bound to the relentless fight against Muzan Kibutsuji.

Who started this institution, and why did he/she develop such a powerful organization? So far, no disclosure has been made on the source of funding that has supported the Corps for so long.

4. What is the Infinity Castle?

Sanemi and Obanai see the Infinity Castle (Image via Ufotable)

Infinity Castle is a teleportation-based structure, changing and growing constantly, known as the residence of Muzan Kibutsuji and his Upper Moon chapters. This situation indicates that the architecture of the castle is intricate, consisting of rotating floors and walls, which would have been impossible for anyone to solve without the guidance of Muzan.

This enigmatic fortress is not only a place but also a representation of Muzan’s megalomania. There is still much to learn about the castle besides its true identity and what it conceals about Muzan’s rule over demons. Infinity Castle represents Muzan’s power and the steep price the Demon Slayers are to pay if they wish to face him within its walls.

5. Why Nezuko was turned into a demon?

Nezuko protecting Tanjiro (Image via Ufotable)

The first episode of Demon Slayer arcs can be traced back to Muzan Kibutsuji turning Nezuko Kamado into a demon. Nevertheless, why Muzan decided to turn to Nezuko has not been well explained. Muzan kills the entire Kamado family, and a lone survivor is transformed into a demon, which was Nezuko.

Was it sheer luck, or did Nezuko have something that Muzan would have wanted? The fact that Nezuko was able to survive and even have the powers of a demon makes it plausible to believe that there could have been a reason why Muzan decided to turn her into a demon in the first place, which makes it one of the most interesting Demon Slayer mysteries.

6. Origin of the Blue Spider Lily

The Blue Spider Lily was meant to cure Kibutsuji Muzan's terminal illness, but the incomplete remedy transformed him into an immortal, human-eating demon vulnerable to sunlight. Muzan, now free from his ailment, mercilessly killed his family in his insatiable hunger.

Determined to perfect the cure, he created the Upper Moon, an elite group of demons, to help him find the rare Blue Spider Lily. Muzan's ultimate goal is to obtain a blooming Blue Spider Lily bud to complete the cure, allowing him to walk in the sunlight without any adverse effects.

7. Origin of Demon Slayer Mark

The Origin of the Demon Slayer Mark is one of the most anticipated Demon Slayer mysteries for fans. The Demon Slayer Mark is a special symbol on the body that makes the wearer stronger than before, particularly in a fight. The first known user of this mark was Yoriichi Tsugikuni. Nonetheless, the history and evolution of the mark are still quite obscure.

Why did Yoriichi have it in the beginning, and how did Tanjiro Kamado come to awaken its power centuries later? The mark is contracted with certain strains of blood or perhaps with particular situations. In other words, there are certain links between the bearers and the history of demon elimination.

8. Will Tanjiro Kamado become a Hashira?

Tanjiro Kamado in the Hashira Training Arc (Image via Ufotable)

As Tanjiro trains under the Hashira and hones his skills, the question arises: could Tanjiro himself become a Hashira? His commitment and his skill to develop incredible moves, such as the Dance of the Fire God, increases his chances of being one.

However, for someone to become a Hashira, it is crucial to possess not only physical strength but also the spirit to approach the grimness of demon killing. Whether Tanjiro can become this Demon Slayer rank adds suspense to the character's growth and the story.

9. Why Was Zenitsu Serious at the End?

Zenitsu Agatsuma, often depicted as cowardly, showed a sudden shift in demeanor towards the end of the Hashira Training Arc. After receiving a mysterious letter, Zenitsu became solemn, a stark contrast to his usual self during training.

This letter seemed to set him on a different path than Tanjiro and the others. In the finale, as he falls into the Infinity Castle, Zenitsu appears emotionless, wholly focused on his new, undisclosed goal. This unexpected change hints at a deeper resolve and a significant personal mission that remains a mystery to fans.

10. Who is the Biwa Demon?

Nakime to look into a new area (Image via Ufotable)

The identity and true nature of the Biwa Demon, Nakime, remains one of the intriguing Demon Slayer mysteries. Introduced during the Hashira Training Arc, Nakime controls the ever-changing Infinity Castle with her biwa, a traditional Japanese lute.

Her ability to manipulate the castle's layout by playing her instrument creates an impenetrable maze, confounding intruders and aiding Muzan Kibutsuji’s defenses. How did Nakime gain such unique powers, and what is her connection to Muzan? The full extent of her abilities and her backstory remains among the other largely unexplored Demon Slayer mysteries.

To Conclude

Thus, having gone through these ten unresolved Demon Slayer mysteries from the Hashira Training Arc, it is safe to conclude that Demon Slayer is worthy of attention in terms of its plotline and character progression.

Such Demon Slayer mysteries create fascinating fan conspiracies and prove the scope of Koyoharu Gotouge’s work. Each enigma, ranging from the founder of the Demon Slayer corps to the origin of demons, makes the Demon Slayer universe all the more compelling.

As the series unfolds, fans look forward to the unraveling of these Demon Slayer mysteries, fully aware that each answer will stir up several more questions in their minds. Through the Hashira Training Arc, fans have been provided with the foundational context to look forward to these unsolved Demon Slayer mysteries.