Tatsuki Fujimoto's *Chainsaw Man* has roared back into the spotlight with its first feature film, *Chainsaw Man – The Movie: Reze Arc*, which has been crushing it at the box office since its release.
The film’s score was once again handled by Kensuke Ushio, the composer for the TV series, but this time he flipped the script, crafting a soundscape with a completely different and richer emotional palette. Japanese pop culture site Natalie sat down with Ushio to get the inside story on his creative process and his take on the explosive world of *Chainsaw Man*.
"This Thing is Pure Chaos"
Ushio recalls being incredibly nervous when he first got the offer to score the *Chainsaw Man* TV anime back in 2022. "I mean, this is a hit manga from *Weekly Shonen Jump*," he said. "Although, when you really look at it, you start to wonder, 'Is this *really* a mainstream shonen series?' (laughs)." He admitted to having doubts about whether he was the right fit, but the passionate invitation from the team at MAPPA convinced him to take on the challenge.
"My first thought reading the manga was, 'This is an absolute mess!' But that chaos is what makes it so compelling. I figured it would be fun to just make 'chaos' the central theme of the music," he explained. The world of *Chainsaw Man* is packed with unpredictable twists, and its characters often think in ways that defy logic. "That 'what the hell is going on' feeling is the core of the series. As long as I kept that in mind, I felt like I could go wild with the music."
The Reze Arc: Swapping AI for Raw Emotion
For the TV series, Ushio made waves by using AI to generate music, but for *Chainsaw Man – The Movie: Reze Arc*, he took a completely different direction.
"I barely used any AI this time, because I always knew that if I got the chance to do the Reze Arc, I wanted to use a large-scale orchestra. The atmosphere of this arc is more lyrical and romantic than the first half, with themes like 'first love' and 'summer'—these fleeting, melancholic feelings. Using AI to blur things would just ruin that sense of authenticity." He added with a laugh, "This movie is like a flower blooming in a world of chaos, and I wanted the audience to hear the sound of that flower opening."
The Story Behind "in the pool": Reze's Secret Theme
One of the film's most memorable musical moments is the track "in the pool," which plays during Reze and Denji's scene at the swimming pool. Ushio revealed that this was actually one of Reze's main themes. "We had two candidates at first. One eventually became 'Reze,' and the other was 'in the pool.' Both the director, Tatsuya Yoshihara, and I felt the pool track captured Reze's essence better, but other producers thought it was too somber. In the end, 'Reze' became the primary theme, but we always privately called 'in the pool' 'our track.'"
Yoshihara even joked, "We were determined to get 'our track' into the final cut. And we did—it even became a full suite version." The piece opens with Reze's line, "Wanna go for a swim?" and builds from soft strings to a sweeping orchestral arrangement, symbolizing the delicate yet dangerous distance between the two characters. "I wanted it to be like a slowly melting concerto—gentle but with a touch of coldness, letting you feel the loneliness she carries," Ushio said.
▼ "in the pool"
The Future of *Chainsaw Man*'s Music
For Ushio, composing for *Chainsaw Man* has been a chaotic adventure. "I'm not just writing background music; I'm trying to find the voice of the characters. No matter how messy or bloody the world gets, the melody of emotion will never be drowned out." For fans, the movie's soundtrack isn't just an extension of the series—it's an emotional journey all its own.
Q: Can you tell us about the orchestral arrangement process? This seems like the largest-scale project you've ever worked on.
Kensuke Ushio: This was definitely the biggest ensemble I've ever been a part of. The simple stuff I can handle by programming beats on a computer, but since my background is in techno, writing a full string score is a bit beyond my skillset (laughs). So, I wrote the melodies and structure on piano and then handed it off to my partner, who handled the arrangement and orchestration (the process of assigning parts to each instrument for a full score). We worked together on the overall orchestral design. Luckily, he's the kind of person who finds my weird ideas fun, which was a huge help.
But there's one thing I really want to point out: after the scene where "Reze and Denji face each other in the pool," you can hear a sound in the background with a "modern Russian piano concerto" style. I wanted the music to evoke the feeling of a "chill from a cold country" gradually closing in, hinting at Reze's background. The orchestrator and I discussed it endlessly, and he managed to weave it perfectly into the piece. The music starts with a heart-pounding, delicate, and sweet melody, then slowly shifts to a more oppressive and cold atmosphere—which perfectly mirrors Reze's backstory. I think we really nailed it.
Q: Reze's Russian song, "Jane wa Kyōkai de Nemutta" (Lyrics: Tatsuki Fujimoto / Music: Kensuke Ushio), was also very memorable.
Kensuke Ushio: The lyrics for that song came directly from the lines in the original manga. The manga panel even had musical notes drawn next to it, so I thought, "Ah, this must be a song," and I tried composing it. I was super nervous, though, because it's in Russian, and I was worried about messing up the phrasing. So when I was writing the music, I paid close attention to matching the rhythm to the meaning of the words to give it the sad-but-not-tragic feel of a Russian folk song.
Also, fitting that many lyrics into an 80-second song while matching the rhythm of the animation was a mission-impossible-level challenge. But thankfully, Reze's voice actress, Reina Ueda, delivered an incredible performance, and the result was absolutely perfect. The track is on the soundtrack, and I really hope everyone gives it a listen on its own.
▼ "Jane wa Kyōkai de Nemutta"
Q: Once the action kicks in, it feels like you're right in your element as a techno musician.
Kensuke Ushio: You could say that. The sound director, the directing team, and I all discussed which tracks should go where. But the second half of the movie is almost non-stop action. If you keep the intensity cranked to eleven the whole time, the pacing gets too dense and the audience gets tired. That "always hype" state is like a rookie DJ who doesn't know how to control the energy (laughs); people just get numb to it. So I was very conscious of the overall dynamics. It couldn't just be a constant barrage of sound. It was more like planning a "live show that doesn't spiral out of control," with carefully arranged peaks and lulls.
Basically, it's the "live set mentality" I use in electronic music. I don't DJ, but when I perform live, I design the flow of the music. The pacing of this film was designed with that same approach. For example, the techno track "sweet danger" yanks the audience from the intimate festival scene right back into the menacing aura Reze projects when she reveals her true self. I love that kind of arrangement.
Q: The music for the *Reze Arc* feels like a fusion of the techno and lyrical styles you've been developing throughout your career, from *Ping Pong the Animation* and *Devilman Crybaby* to now.
Kensuke Ushio: It's true (laughs). The sound director, Mr. Nagura, was also the mixer on *A Silent Voice* and *Liz and the Blue Bird*. I was part of his team on those projects, so he gets me, and he gave me a lot of creative freedom this time. Normally, deciding which track goes where is the job of the sound director or music selector, but Mr. Nagura trusted me to map out the entire musical structure myself.
I'm hesitant to use a word like "culmination," but this project was definitely the result of all my experiences converging. Being able to use my own musical language to bring *Chainsaw Man – The Movie: Reze Arc* to life... I feel like this was truly an ideal outcome.
From the TV series to the movie, Kensuke Ushio's dedication to the music of *Chainsaw Man* is nothing short of incredible. The film's soundtrack, which seamlessly blends lyrical emotion, high-octane electronica, and chilling tension, has earned rave reviews from audiences for its power to immerse them completely in the story.
With a string of acclaimed projects like *Ping Pong the Animation*, *Devilman Crybaby*, *The Heike Story*, and *Dandadan* under his belt, Ushio's schedule is packed. It's safe to say we can expect even more amazing work from him in the future.
via： Natalie