Aizetsu

Aizetsu is a male demon and one of Hantengu’s split bodies, specifically representing “sorrow.”

He appears as a young man wearing work-style robes with a sash tied across his chest, wielding a large cross-shaped spear.

True to his name, he frequently mutters that things are “sad” and speaks in a very low-energy, downbeat tone.

Despite this, he is not actually pessimistic; he can be surprisingly assertive and even confident in battle.

Among Hantengu’s clones, Aizetsu is second only to Sekido in calmness and rationality.

He rarely drops his guard, which strongly contrasts with the more reckless, overconfident Karaku and Urogi, who often leave openings because of their carefree or excited temperaments.

In the anime adaptation, his voice actor is Soma Saito.

His visual design differs somewhat between manga, anime, and novelized material, which has led fans to notice and discuss these variations.

Aizetsu’s defining emotional axis is sorrow.

He repeatedly comments on how “sad” various things are, almost like a quiet running commentary on how bleak the situation seems to him.

His mood is consistently low-key, and his speech is soft and subdued.

Even so, he does not crumble under pressure; instead, he stays composed and sometimes talks back with unexpected boldness.

Unlike Hantengu’s other clones, Aizetsu avoids arrogance or showy behavior.

This makes him a stable, tactical presence in battle, more akin to a stoic warrior than an emotional berserker.

Compared to the hedonistic Karaku, the hyper Urogi, and the furious Sekido and Zohakuten, Aizetsu’s personality is almost unique in the entire series.

He is a reserved, melancholic fighter whose brand of quiet gloom stands out in a cast full of explosive emotions.

Aizetsu specializes in spear-based combat and uses his weapon to generate deadly shockwave attacks.

Among Hantengu’s clones, his technique is notable for being a straightforward physical attack rather than an elemental or purely ranged ability.

Gekirui Stab (Gekirui Shitotsu)

Aizetsu thrusts his cross-shaped spear forward and releases five shockwave-like attacks in front of him.

These projected stabs act as high-speed, long-range strikes, making it difficult for opponents to approach safely.

Within the context of the story, this move has extremely high lethality.

For an ordinary human, taking a direct hit would almost certainly result in instant death.

Ironically, Aizetsu’s signature technique is shown mostly against Genya Shinazugawa, whose unusual constitution allows him to survive being impaled.

Because of this match-up, the narrative never fully showcases the true lethality of the move, making Aizetsu feel somewhat underutilized despite arguably wielding the most outright deadly technique among the four clones.

Aizetsu first appears when he emerges from Sekido’s neck as one of Hantengu’s emotional manifestations.

He joins the battle during the Swordsmith Village arc.

Battle with Genya Shinazugawa

At the start of his appearance, Aizetsu engages Genya Shinazugawa in close-quarters combat.

He repeatedly impales Genya with his spear and shockwaves, but Genya’s extreme durability and partial demonization prevent these attacks from becoming fatal.

While Tanjiro Kamado is occupied fighting Karaku, Urogi, and Sekido, Aizetsu focuses on Genya.

However, during the chaos of the ongoing fight, Genya manages to decapitate Aizetsu when the demon lowers his guard for a moment.

At this point, Genya consumes part of Aizetsu’s body, using his flesh to further strengthen his own demonization ability.

This act directly ties Aizetsu to Genya’s power-up and the later stages of the battle.

Return and Final Fate

After regenerating, Aizetsu resumes fighting, this time clashing with Nezuko Kamado and Genya.

Even with his powerful spear and shockwaves, he cannot deliver a decisive finishing blow against either opponent, leading to a prolonged stalemate.

As the tide of battle turns and Hantengu’s true body is on the verge of decapitation, the situation changes.

Aizetsu, along with the other clones, is pulled back and absorbed by Sekido, contributing to the formation or empowerment of Zohakuten.

When he is being absorbed, Aizetsu opens his mouth as if to protest or voice an objection.

However, he disappears before he can say anything, his final words swallowed along with his body, which fits the quietly tragic tone of his character.

In the second official popularity poll, Aizetsu received 8 votes, placing him at 101st.

Interestingly, this put him just behind Hantengu himself, who ranked 62nd with 28 votes.

During that poll, only results up to 101st place were published, and Aizetsu barely made the cutoff.

Fans sometimes point out that this is oddly fitting for his “sad” persona, but it also highlights that he left enough of an impression to be remembered despite limited screen time.

Other characters and entities that received the same 8 votes included Kiriya Ubuyashiki’s sister Kanata Ubuyashiki and the bear that Tanjuro Kamado once killed.

By contrast, the other Hantengu-related forms and clones, including Zohakuten and the rest of the group, did not even make it into the ranking list, making Aizetsu’s small but solid fan presence stand out.

His uniqueness in the series likely contributes to this niche popularity.

No other character embodies a similarly quiet, sorrowful yet composed demeanor paired with such a brutal physical fighting style.

Aizetsu’s animation and expressions in the anime spawned a number of jokes among fans.

One of the most talked-about moments is his expression and body language when he is being absorbed by Sekido.

As he raises his hands and makes a hesitant, resigned face, fans jokingly compare him to a customer at a convenience store politely refusing disposable chopsticks.

This “no thanks” pose became a meme, playing off how understated and politely miserable he looks even in a dire situation.

Another popular fan joke revolves around his clothes.

In the anime, Aizetsu’s work-style outfit, which is meant to be traditional, has a cut and color scheme that many viewers say looks like a tracksuit or sportswear.

Because of this, some fans nicknamed him the “Tracksuit Demon.”

The contrast between his gloomy personality and the casual, almost athletic look of his outfit adds to his comedic and meme-worthy appeal.

Aizetsu’s appearance has noticeable differences between the manga, the anime, and the novelization.

These changes affect details such as his face, outfit, and eye color descriptions.

In the original manga, his sleeves form a kind of hand guard, extending over the backs of his hands and hooking around his middle fingers.

This creates a more martial, specialized look appropriate for a spear-wielding fighter.

In the anime, the sleeves are altered to end at the wrist like normal clothing.

This simpler design contributes to the “tracksuit” impression and changes his silhouette slightly.

His facial structure also differs.

In the manga, Aizetsu has a rounder, softer face, making him look somewhat younger and more boyish than Sekido, Karaku, and Urogi.

In the anime, his facial features are sharpened so that he appears closer in age and maturity to the other three clones.

This makes the quartet feel more cohesive as a group but also reduces the childlike nuance present in his manga design.

Both manga and anime depict Aizetsu with blue eyes.

However, the novelization once describes him as looking down at Genya with “bright red eyes.”

It is unclear whether this discrepancy is due to the novel’s author not having final character color references at the time of writing, or if it was simply an error.

Either way, it stands out to detail-oriented fans as a curious mismatch between media.

Overall, these variations across adaptations demonstrate how even a relatively minor but memorable character like Aizetsu can evolve visually and tonally.

His blend of sorrowful temperament, deadly technique, and quietly comedic moments ensures he remains a distinctive presence in Demon Slayer: Kimetsu no Yaiba.