Zenitsu’s Letter in Demon Slayer Makes Him the Anime’s Most Important Character

Of all the warriors introduced in the hit anime Demon Slayer, one of the weakest and meekest is Zenitsu Agatsuma. However, after receiving a pivotal letter, Zenitsu is poised to become one of the most important in the entire Demon Slayer series.

Who Is Zenitsu in Demon Slayer?

Despite his role as a Demon Slayer, the highly trained warriors who travel across feudal Japan slaying insidious demons preying on humans, Zenitsu developed a reputation as a coward. Constantly in a state of fear, Zenitsu often panics at the earliest sign of trouble and prefers to cut and run rather than stay and fight, in direct opposition to his duties and role as a Demon Slayer. Painfully self-aware of his own cowardice, Zenitsu privately wishes he was braver and strives to be a more dependable warrior to help his friends fight the increasingly formidable demons they encounter.

One person that Zenitsu holds in especially high esteem is his venerable mentor, Jigoro Kuwajima, who always believed in him despite his annoying behavior. Seen in flashbacks to Zenitsu’s early training as a Demon Slayer, Jigoro teaches his pupil a vital breathing technique that helps him maintain his composure in the heat and anxiety of battle. However, in Demon Slayer Season 4, Zenitsu receives a letter from Chuntaro, one of the Kasugai Crows used by the Demon Slayer Corps for long-distance communication, that changes Zenitsu forever.

What Is in Zenitsu’s Letter?

The letter that Zenitsu receives from Chuntaro in the seventh episode of Season 4 informs him of the full, tragic nature of Jigoro’s death. Zenitsu learns that Jigoro felt responsible for the corruption of fellow Demon Slayer and Thunder Hashira pupil Kaigaku, who decided to betray the Demon Slayer Corps and become a demon himself. With Jigoro having extensively taught Kaigaku powerful techniques derived from the Thunder Hashira, Jigoro fears the destructive potential he empowered his former student with that will now be used towards evil.

Overwhelmed by shame, guilt, and horror, Jigoro decided to take his own life by committing seppuku, slicing open his own belly while kneeling. As Jigoro was all alone when he took his own life, he had no one with him to finish him off, as per Japanese tradition regarding seppuku, meaning that he spent his final moments in complete agony as his innards were exposed. The letter’s reveal is one of the darkest moments yet in the Demon Slayer anime, and given the story’s grim carnage, that’s really saying something.

The Impact the Letter Has on Zenitsu and Demon Slayer

As soon as Zenitsu learns about his master’s painful and solitary death, his entire demeanor changes to one audiences have never really seen before from him. No longer the meek and easily scared individual, there is a seriousness and drive to Zenitsu that is immediately visible. This is compounded when Zenitsu shares this information with Kaigaku, who shows no remorse for Jigoro’s death and remains spiteful of his old mentor.

With this new demeanor, Zenitsu is poised to become one of the most committed warriors in the Demon Slayer Corps as they face off against Kaigaku and his demonic associates. No longer hiding on the sidelines and looking to avoid fights, Zenitsu is out to clear his mentor’s name and restore his legacy rather than as one disgraced for teaching the traitorous Kaigaku the Thunder Breathing techniques. Tanjiro Kamado may still be the overarching protagonist of Demon Slayer for the time being, but Zenitsu has just stepped up in a big way with personal stakes to take the demon army down.

Demon Slayer is streaming now on Crunchyroll.