An Entrance Straight Out of the Movie
Neither actor bothered with a normal walk-on. Hiro Shimono announced himself from the wings by calling out Zenitsu's Thunder Breathing Seventh Form, Honoikazuchi no Kami, before introducing himself to the crowd. Yoshimasa Hosoya followed with Kaigaku's Sixth Form, Rumble and Flash (Dengō Raigō), and the theater answered with a roar of cheers and applause, according to the event report from Japanese anime news outlet Anime Anime.
In the story, Zenitsu and Kaigaku are former brother disciples who trained under the cultivator Jigoro Kuwajima, and their ferocious clash plays out in this film. Despite that, the two actors had somehow never appeared at an event together until now. For Hosoya (Reiner Braun in Attack on Titan), it went further: this was his first Demon Slayer event of any kind, and he told the audience he was moved just to be there.
Shimono set the tone early. Their characters spend the film trying to kill each other, he noted, but on stage they would be playing cooperatively. Hosoya replied, "We get along well." Aniplex producer Yuma Takahashi handled MC duties for the evening.
Shimono Didn't Always Love Kaigaku
The fan Q&A produced the night's most striking admission. Asked which scene deserves repeat viewings, Shimono picked the flashback between Zenitsu and Kaigaku, then confessed he did not actually like Kaigaku until he recorded the film. Working through Zenitsu's feelings during the fight, he came to see Kaigaku as someone Zenitsu admired, a hateful figure who was nonetheless something close to family. That, he explained, is where Zenitsu's line "I'm sorry, big brother" comes from. He asked fans to rewatch the buildup to Honoikazuchi no Kami with all of Zenitsu's conflicted feelings in mind.
The session itself carried unusual weight for him. Shigeru Chiba, who voices their late master Jigoro Kuwajima, joined the recording, and Hosoya recalled that Shimono, normally the person keeping the studio loose, was locked in that day. Shimono agreed, saying that of all his Demon Slayer sessions, this one may have left him the most nervous. Sessions usually revolve around Natsuki Hanae's Tanjiro, he explained, but for the Zenitsu and Kaigaku scenes he felt he had to set the emotional tone himself.
Hosoya's Case for Kaigaku
Hosoya recommended rewatching the full fight, flashbacks included, saying the two characters' competing arguments capture something nakedly human, foolishness and cunning both. He laid out Kaigaku's grievance with real sympathy: the man mastered every Thunder Breathing form except the First, apprenticed earlier than Zenitsu, and honed his craft for years, only to be told to share the succession with his junior. Anyone would resent that, he argued.
Asked what he sees in Kaigaku roughly a year after the film opened, Hosoya pointed to experiences most people recognize. Talented people get passed over because of an evaluator's personal preferences, charm gets rewarded over ability, and jealousy after an unfair loss is universal. With the necessary caveat that Kaigaku's actions are hardly praiseworthy, Hosoya said someone that honest about his own desires is living life in earnest, "so I don't dislike him."
He closed by thanking fans directly, saying he only got to stand on that stage because people loved Kaigaku and kept championing the character.
Looking Ahead
The film that occasioned all this, Demon Slayer: Kimetsu no Yaiba Infinity Castle Chapter 1: Akaza Returns, hit Japanese Blu-ray and DVD on July 29, 2026. Japanese audiences also get one more theatrical window soon: Anime Anime reported that Mugen Train and Infinity Castle Chapter 1 return to theaters for one week, August 21 through 27, with one screening of each per day at Grand Cinema Sunshine Ikebukuro.
International fans are already covered. After a worldwide theatrical run that Forbes put at roughly $794 million, the film has been streaming on Crunchyroll since July 28, 2026, with the English dub and a wide range of subtitle options. It is the first entry in the Infinity Castle trilogy; the event brought no news on the second film's timing. The source manga by Koyoharu Gotouge is published in English by Viz Media.