Set to release in July 2025, Demon Slayer: Kimetsu no Yaiba – Infinity Castle Arc is one of the most anticipated films worldwide.
This cinematic masterpiece, which has redefined the history of Japanese manga and anime, is finally entering its final chapter.

In this article, we’ll take a deep dive into the characters that appear in this epic saga—uncovering what makes each of them truly compelling.
Whether you’re a long-time Demon Slayer fan or a newcomer to the series, this guide is perfect for both a refresher and a primer.

This article introduces Zenitsu Agatsuma, one of the main characters in Demon Slayer: Kimetsu no Yaiba.
Known for his cowardly demeanor and comedic moments, Zenitsu surprises both allies and enemies alike with his incredible speed and swordsmanship when pushed to his limits. His growth and inner strength make him a memorable and beloved character throughout the series.

◆What is "Demon Slayer"?

Originally serialized in Weekly Shonen Jump from February 2016 to May 2020, Demon Slayer: Kimetsu no Yaiba has surpassed 150 million copies in cumulative manga sales. Set in Japan's Taisho era, the story follows Tanjiro Kamado, a young boy who joins the Demon Slayer Corps after his family is slaughtered by demons and his sister Nezuko is turned into one. His mission: to find a way to turn her back into a human.

The anime adaptation began with the Tanjiro Kamado, Unwavering Resolve Arc broadcast in 2019, followed by the record-breaking release of Demon Slayer: Mugen Train in October 2020. The saga continued with the Entertainment District Arc in December 2021, the Swordsmith Village Arc in April 2023, and most recently, the Hashira Training Arc aired from May to June 2024.

The upcoming Infinity Castle Arc serves as the direct sequel to the Hashira Training Arc and will be presented as a three-part theatrical release.

◆Who is Zenitsu Agatsuma?

Full Name and Pronunciation: Zenitsu Agatsuma (あがつま ぜんいつ / Agatsuma Zenitsu)
Birthday: September 3 (Virgo)
Age: Around 16 years old at the beginning of the story
Height/Weight: 164.5cm / 58kg
Affiliation/Rank: Demon Slayer Corps / One of the survivors of the Final Selection (initially at the lowest rank "Mizunoto")
Birthplace: Specific birthplace unknown
Weapons/Special Skills:
Nichirin Sword (yellow blade)
Extremely acute hearing, allowing him to distinguish various "sounds" with special ability
First Appearance:
Manga: Volume 3 (Chapter 21)
Anime: Episode 11 "The Drum House"

Physical Characteristics
A young boy with yellow hair and bright orange eyes. He wears the Demon Slayer uniform with a checkered haori over it. He usually has a frightened expression or tearful face, but when he enters his "sleeping" state, his expression becomes calm and sharp.

Personality
An extremely cowardly person who lacks confidence in his abilities and constantly makes self-deprecating remarks. He also has an affinity for women, particularly falling in love with Nezuko Kamado at first sight. He tends to panic easily and often cries loudly. However, when the situation demands it, he shows surprising courage and is willing to risk his life for his friends.

Background
Having lost his parents at a young age, he was tricked by swindlers and burdened with a large debt when he was rescued by Jigoro Kuwajima (nicknamed "Gramps"), a former Thunder Hashira. He became Jigoro's disciple and learned Thunder Breathing, but often tried to run away from training, ultimately mastering only the First Form "Thunderclap and Flash" to perfection. After Jigoro's death, he joined the Demon Slayer Corps carrying on his will.

Position in the Story
As one of Tanjiro's peers, he is one of the main companions in the story. Though initially appearing timid and weak, he secretly possesses exceptional talent and becomes an important fighting force as the story progresses. His unique style of continuing to fight with just the "Thunderclap and Flash" technique symbolizes the martial arts path of mastering a single technique.

Important Characteristics and Settings
His most distinctive feature is that when he enters a "sleeping" state, his personality changes, becoming a calm and powerful warrior. The gap between his usual cowardly personality and his strength in battle is a major part of his appeal. Additionally, his excellent hearing allows him to distinguish the "sounds" of humans and demons, predicting their movements.

◆Abilities and Traits

Techniques and Fighting Style
Thunder Breathing: One of the five basic breathing styles alongside Flame, Wind, Stone, and Water. A technique that cuts down enemies with lightning-fast speed.

Mastered Forms:
First Form: Thunderclap and Flash (Hekireki Issen): The only form Zenitsu has completely mastered. A technique involving a super-high-speed rush that cuts down enemies in an instant. He has trained it to the extreme and can perform up to six consecutive strikes.

Seventh Form: Honoikazuchi no Kami (God of Fire and Thunder): A form Zenitsu developed independently. A technique that exists beyond the mastery of Thunderclap and Flash, used in the final battle against Muzan.

Special Abilities
Super Hearing: The ability to distinguish the "sounds" of people and demons, sensing the "threads" of their movements.
Sleeping State: When he faints from fear or tension, he enters a "sleeping" state where his latent abilities are released. In this state, he displays strength inconceivable during his normal state.

Ability Development Throughout Growth
Initially only able to use Thunderclap and Flash, but with battle experience, the precision and speed of his technique improved. Starting with a single strike, he progressed to two strikes, three strikes, and eventually up to six consecutive strikes. In the latter half of the story, he developed his own form "God of Fire and Thunder," acquiring a more powerful technique.

Distinctive Battle Scenes
Battle at the Drum House: The first time he entered his "sleeping" state and demonstrated his true abilities.
Battle with Enmu on the Infinity Train: Despite being shown a happy life with Nezuko in his dreams, he realized it was an illusion and demonstrated strong mental fortitude by waking up on his own.
Confrontation with Kaigaku: A battle with his former fellow disciple who killed his master Jigoro. He used "God of Fire and Thunder" for the first time and achieved his revenge.

Strengths and Weaknesses
Strengths:
Super-speed slashes from "First Form: Thunderclap and Flash" taken to the extreme
Predicting enemy movements with exceptional hearing
Calm judgment and combat ability in the "sleeping" state

Weaknesses:
Extreme fear and lack of confidence in normal state
Unable to master forms other than Thunderclap and Flash (until later acquiring "God of Fire and Thunder")
Prone to panic due to his personality

◆Relationships

Family
Parents: Mentioned to have passed away at a young age
Jigoro Kuwajima: Not blood-related but his foster parent and master, former Thunder Hashira of the Demon Slayer Corps
Kaigaku: Also a disciple of Jigoro, Zenitsu's "senior disciple," who later became a demon and killed their master

Colleagues and Companions
Tanjiro Kamado: A peer in the Demon Slayer Corps. They trust each other as close friends. Zenitsu is impressed by Tanjiro's kindness.
Inosuke Hashibira: Another peer in the Demon Slayer Corps. They initially clashed but gradually built a relationship of trust.
Kanao Tsuyuri: A training companion at the Butterfly Mansion. He respects her strength and quiet personality.

Romantic Relationships
Nezuko Kamado: He falls in love with her at first sight and harbors strong romantic feelings. In the latter half of the story, he repeatedly risks his life to protect her.

Important Interaction Episodes
Training with Jigoro: Despite running away, he perfected Thunderclap and Flash under Jigoro's strict but loving guidance.
Meeting with Tanjiro: Initially cowering in fear when they first met, he came to trust Tanjiro after experiencing his sense of justice and kindness.
Feelings for Nezuko: Upon first seeing Nezuko emerge from her box, he fell in love at first sight and vowed to protect her.

◆ Official Character Popularity Poll Results

Zenitsu boasts phenomenal popularity in the "Demon Slayer" official popularity polls.

🔹 1st Popularity Poll (Weekly Shonen Jump, 2017)
Rank: 2nd
Votes: 6,842

🔹 2nd Popularity Poll (2020)
Rank: 1st
Votes: 17,451

💬 What Fans Love About Zenitsu
Relatability: His typically cowardly and weak appearance makes it easy for readers/viewers to empathize with him.
Appeal of the Gap: The contrast between his usual frightened appearance and his coolness when asleep.
Comic Elements: His panicked state and reactions to women contribute many comedic moments to the series.
Growth Story: Many readers are moved by his commitment to believing in and perfecting a single technique.
Pure Feelings for Nezuko: His devoted love for the heroine is widely supported.

Evaluation in the Fan Community
On social media and video sites, scenes featuring "Sleeping Zenitsu" are particularly popular. Additionally, the pairing of Zenitsu and Nezuko (known as "ZenNezu") is a frequent subject of fan art and fan fiction. The concept of compensating for the limitation of using only one form by perfecting that form is appreciated as resonating with the Japanese martial arts philosophy of "mastering a single art."

◆ Voice Actor: Hiro Shimono

Hiro Shimono (下野紘) A renowned voice actor who, besides "Demon Slayer," has voiced many major characters such as Soma Yukihira in "Food Wars!" and Asta in "Black Clover."

Hiro Shimono made his voice acting debut in 2001 and has since become one of the most recognizable male voice actors in the Japanese anime industry. His versatility allows him to voice a wide range of characters, from energetic and comedic roles to serious and emotional performances.

His portrayal of Zenitsu Agatsuma in "Demon Slayer: Kimetsu no Yaiba" has been particularly praised and is widely considered one of his signature roles. The character's frequent shifts between extreme cowardice and fierce concentration in battle allowed Shimono to showcase his impressive vocal range and emotional expressiveness.

Notable Roles
Beyond Zenitsu Agatsuma in "Demon Slayer," Hiro Shimono has voiced numerous significant characters in popular anime:
Sho Kurusu in "Uta no Prince-sama" series
Connie Springer in "Attack on Titan"
Yūichirō Tajima in "Big Windup!"
Dabi in "My Hero Academia"
Rex in "Xenoblade Chronicles 2"
Natsuki Subaru in "Re:Zero − Starting Life in Another World"
Hanzō Urushihara in "The Devil Is a Part-Timer!"
Keima Katsuragi in "The World God Only Knows"
Awards and Recognition

Hiro Shimono's talents have been recognized through various awards in the voice acting industry:
15th Seiyuu Awards (2021): Most Valuable Seiyuu (MVS) - This prestigious award is determined by fan votes and recognizes the most accomplished voice actor of the year.
His work as Zenitsu in "Demon Slayer" has been particularly acclaimed and contributed significantly to his MVS win.
He has also been nominated for various supporting role awards throughout his career.
Performance as Zenitsu Agatsuma

Shimono's performance as Zenitsu has been widely praised for several distinctive aspects:
Vocal Range: His ability to shift between Zenitsu's high-pitched, panicky screams to the calm, focused tone when the character is asleep showcases his impressive range.
Emotional Expressiveness: Critics and fans have lauded his authentic portrayal of Zenitsu's extreme emotions, particularly his fear and anxiety.
Comic Timing: His delivery of Zenitsu's comedic lines and reactions has been noted for its perfect timing and energy.
Character Transformation: Shimono's ability to convey the stark contrast between Zenitsu's conscious and unconscious states is considered a highlight of his performance.

When Will Be Released "Demon Slayer: Infinity Castle Arc"?

It is scheduled to premiere in Japanese theaters on Friday, July 18, 2025.
In North America (the United States and Canada), the theatrical release is planned for Friday, September 12, 2025. It will be shown in formats including IMAX and other premium screens, with Japanese audio and English subtitles, as well as an English dubbed version.

Please check for the latest updates regarding release and streaming information in other regions.

Teaser Movie 1: Demon Slayer Infinity Castle Arc

Teaser Movie 2: Demon Slayer Infinity Castle Arc

Source : DemonSlayer Official