Since its June debut, Netflix’s KPop Demon Hunters has been rewriting the rulebook for animated musicals, becoming nothing short of a cultural phenomenon. The colorful animated fantasy, directed by Maggie Kang and Chris Appelhans and produced by Sony Pictures Animation, has surged to become Netflix’s most-streamed original animated film of all time alongside becoming the streaming platform's most-watched film of all time as of Aug.27. With more than 236 million views worldwide, it landed in the Global Top 10 for five consecutive weeks, reached #1 in 26 countries, and is on track to break Netflix’s all-time movie record.

Its music has proven just as unstoppable. The breakout single Golden — performed in the film by Huntr/x but brought to life by real artists Ejae (an SM Entertainment alum), Korean American singer Audrey Nuna, and Rei Ami — has become a once-in-a-generation hit. It topped the Billboard Hot 100 in the U.S. and the British Official Singles Chart Top 100 for four consecutive weeks, becoming the first K-pop song to reach #1 in the U.K. in 13 years since Psy’s Gangnam Style. It also marked the first time a track from a fictional girl group reached the top of Billboard’s Streaming Songs chart, with Golden now the most streamed song in the United States.

The soundtrack’s success goes far beyond a single hit. In a feat unseen since Waiting to Exhale in 1995, KPop Demon Hunters placed multiple tracks in the Billboard Hot 100’s Top 10 simultaneously. Alongside Golden, Huntr/x has sent several songs soaring into the charts, including How It’s Done (which just cracked the Top 10), What It Sounds Like, and Takedown, which climbed to #25. Incredibly, Golden has now spent multiple nonconsecutive weeks at #1 on the Hot 100, while other tracks continue to climb. Not to be outdone, the villainous Saja Boys have also stormed the charts, sending their entire fictional discography into the Top 10. Their singles Your Idol and Soda Pop are holding strong at #4 and #5, respectively, while other songs continue to rise. No soundtrack has managed that kind of dominance since "Saturday Night Fever" in 1978, according to Billboard. On Spotify, Soda Pop even surpassed BTS’s Dynamite as the highest-charting K-pop boy group single, peaking at #2 globally.

This unprecedented moment marks the first time in history that two entirely fictional K-pop groups have not only debuted but also dominated the most competitive music charts in the world. In total, eight songs from the soundtrack have charted on the Hot 100 — a staggering achievement for a project born from a fictional universe. The soundtrack’s dominance has spilled over to global platforms as well, with multiple songs topping Spotify’s U.S. charts, landing in both the #1 and #2 spots. With four songs simultaneously in the Billboard Top 10, KPop Demon Hunters has become the first film in history to achieve this milestone.

KPop Demon Hunters follows HUNTR/X — Rumi, Mira, and Zoey — an all-female K-pop group who dazzle fans on stage while secretly protecting humanity as demon hunters. Their greatest rivals are the Saja Boys, a slick boy band who mask their true identity as soul-devouring demons beneath irresistible charm and polished choreography.

The runaway success of the soundtrack has not only sparked Oscar buzz for Best Original Song consideration, but has also been embraced across the K-pop industry, with endorsements from stars of BTS, EXO, ITZY, and Stray Kids. TikTok challenges tied to the film’s music have generated millions of posts, while fan art, covers, and live sing-along screenings have cemented KPop Demon Hunters as both a box office and cultural juggernaut. Talk of sequels and expanded installments is already underway, as audiences around the world clamor for more.

At the heart of this unprecedented success is Ian Eisendrath, the film’s executive music producer, whose vision helped shape one of the most ambitious animated soundtracks ever created. On KPop Demon Hunters, Eisendrath wore many hats, overseeing every aspect of the score — from conducting and arranging to music and vocal production. Though this marks his first time leading the music on an animated feature, Eisendrath is hardly new to large-scale musical storytelling. An Olivier Award winner and Grammy nominee, he has spent the past two decades building a career that bridges theater, film, and television with equal mastery.

Eisendrath was first approached by Spring Aspers, President of Music at Sony Motion Picture Group, to work on KPop Demon Hunters after their collaboration on Lyle, Lyle, Crocodile. Already acclaimed for his work as music supervisor, arranger, and conductor of the Broadway hit Come From Away, he has also served as executive music producer on high-profile projects including Disney’s Snow White, Hulu’s Only Murders in the Building, Apple TV’s Spirited, and Netflix’s Diana: The Musical. His work has spanned both stage and screen, from live musicals like A Christmas Story: The Musical to Hollywood films featuring stars such as Rachel Zegler, Shawn Mendes, Meryl Streep, Steve Martin, and Ryan Reynolds. That breadth of experience proved crucial for KPop Demon Hunters.

A graduate of the University of Michigan School of Music, where he majored in both theater directing and music, Eisendrath’s philosophy of music dramaturgy — understanding what a song can achieve both musically and narratively — guided his approach. “I think of my job as the integrity of the music from the second the film starts to the second the film is over,” he explains. He believes the first song is key to gaining the audience’s trust and, from there, creating moments where the characters’ singing feels earned and organic. That sensibility proved vital in building a soundtrack that not only moves the story forward but also stands on its own as a collection of chart-topping hits.

Tasked with weaving authentic K-pop into a fantastical storyline, Eisendrath collaborated with a powerhouse creative team, bringing together some of the biggest names in K-pop and beyond — including Teddy Park and Lindgren from Korea’s THEBLACKLABEL, as well as songwriters like EJAE (behind hits for aespa and Red Velvet), Mark Sonnenblick (an Emmy-nominated TV/film writer), Stephen Kirk, and Jenna Andrews, whose credits include BTS singles “Boy With Luv” and “Butter.” He also worked closely with directors Maggie Kang and Chris Appelhans, as well as K-pop idols themselves, including Jeongyeon, Jihyo, and Chaeyoung of TWICE, who recorded “Takedown,” to craft music that feels both cinematic and true to the K-pop genre. His ability to speak both the language of musical theater and the pop industry allowed him to bridge East and West, creating songs that could top the charts while also deepening the film’s characters and storylines.

The result is a soundtrack that doesn’t just support the film — it has become one of the year’s biggest chart phenomena. For Eisendrath, who has built a career on weaving story and song together, KPop Demon Hunters represents the pinnacle of that mission: music that feels true to its characters, yet powerful enough to stand on its own on the global charts.

In our conversation, Eisendrath takes us inside the making of KPop Demon Hunters, revealing how the music was crafted alongside the animation, what it was like collaborating with K-pop’s top producers and vocalists, the creative journey behind the soundtrack, why authenticity was key to transforming a fictional K-pop album into one of the year’s biggest pop phenomena, and how music became the heartbeat of this global hit.

The following are excerpts from a written interview with Ian Eisendrath, conducted via email between July 22 and August 30.

KPop Demon Hunters brings K-pop into a cinematic narrative for perhaps the first time at this scale. How did you first get involved, and what excited you most about its storytelling potential in an animated film?

I was working on another film at Sony, Lyle Lyle Crocodile, with Shawn Mendes. Nearly one week after we wrapped, I got a call from Spring Aspers, who's president of music for Sony Pictures, regarding a new project, and she said you're going to want to get involved with this project. The film’s animation is some of the most incredible I've ever seen. As a huge fan of K-pop music, I had always felt its theatricality would lend itself to film. Naturally, I was super excited to dive in.

As you began shaping the sound of this project, what core ideas defined its musical DNA, and how did the metaphor of music as a battleground influence your approach to genre, tone, and giving each group their own sonic identity? 

First and foremost, we wanted to create K-pop songs that truly landed with the K-pop audience and felt authentic to the genre. The key to achieving that was the K-pop kit makers we brought on-board the project. Spring assembled a stable of K-Pop kit makers: The Black Label, Stephen Kirk and Jenna Andrews, EJAE, and more. With this prolific team, we were able to create narrative songs  that matched the musical qualities of the top chart K-pop songs. That was goal number one: to create songs that are not attempts at recreating K-pop, but songs that are created like K-pop songs by K-pop songwriters. Our second goal was to figure out how to ensure the narrative, the story, and the character elements of the songs worked for the film, all the while maintaining the songs’ stylistic authenticity. It was this wonderful and constant calibration of those two goals (narrative, story-driven songs and true cutting-edge K-pop songs) that were our guiding light throughout the process.

We then had the exciting task of defining the specific sound of the K-pop group at the center of the film’s story. We knew that these hunters were hard-core demon fighters, so this K-pop girl group (HUNTR/X) had to have that fierce and fiery sound. We knew that the Saja Boys had a progression from appearing in a deceptive way – as these sort of naive, innocent bubble gum-like characters who sound harmless – and then they become, you know, unfiltered soul-eating demons by the end of the film. Their music really follows that journey from bubble gum K-pop to really, really dark, heavy, intense K-pop when they arrive singing ‘Your Idol.’

K-pop’s sonic diversity gave you room to explore a wide range of musical styles, resulting in the soundtrack spanning an impressive range. How did you go about crafting such a wide musical palette while balancing that variety with a sense of cohesion across the soundtrack? 

These songs had to move the story forward, and it was deeply joyful and gratifying to watch all these artists from the K-pop world embrace that challenge. They quickly learned how to write for film, which was incredibly exciting to witness. 

At the same time, it was about amplifying the scale of the songs so they felt cinematic and theatrical which was a true collaboration with all the artists involved. We had a vast space to fill with many visual moments that demanded music to match their intensity, so it was a constant process of discovering where the line lies between a K-pop track and a song for cinema. Our team included a wonderfully diverse group of K-pop songwriters and producers, each bringing unique musical voices, tastes, and expertise. I feel like my role was to be the through-line, ensuring we stayed consistent in how we told the film’s musical story.

This project unfolded over several years, with songs and scenes evolving alongside the story. Could you walk us through the songwriting process? From initial concepts to fully produced tracks, how did the songwriting process adapt to that long, iterative timeline to keep pace with the film’s shifting shape? 

Our process for developing the songs was quite gradual and organic. We began by locking in the story beats – what each song needed to say and accomplish , alongside temping in various existing K-pop songs for most slots to find the right vibe, energy, and tempo. Once a sequence was storyboarded enough to make its musical needs clear, the directors and I would meet with the writers and set them on their way. This happened gradually because in animation,  sequences each develop and progress at a different pace. So, songs were launched in whichever areas the directors and producers felt were furthest along in terms of story and sequence.

When meeting with songwriters, we provided rough prose lyrics to outline the song’s purpose, along with multiple musical references. We’d discuss structure, tempo, and other elements until the vision for what we needed was clear. The writers would then create drafts, and we’d refine them through many rounds of feedback. Interestingly, each song found its place differently – some song spots needed six or more different songs written until we figured out what it wanted to be, while others came together far more quickly.

How did you approach building a sonic world, balancing the distinct identity of K-pop with the emotional demands of narrative in a way that they could coexist and elevate one another? 

I've always really been a student and a great admirer of the balancing act of a truly great song from a music perspective, and story. This project demanded exactly that: songs that carried narrative first and foremost, but that could also stand on their own and  live on outside of the film; tracks you’d want to hear on the radio or stream repeatedly on Spotify. 

With that perspective, I felt well positioned to support everyone involved in the project, from directors, producers, songwriters, to music producers, to really create something that worked across all departments. In many ways, I served as the bridge between K-pop music culture and film music culture.

While the animators were developing the visual style of the film, you and your team were simultaneously shaping its soundscape. How did you collaborate with the animation team to ensure the music and visuals worked seamlessly together? 

One of the fun aspects was working closely with our music editor, Oren Yaacoby, and our directors to ensure that we believed the singers were singing when watching the songs against the picture. My job was to respond to what the directors and producers,  who were the central hub for everything, were envisioning, and then make sure the music could carry that through. 

This was a collaboration that went two ways.  We would sometimes re-record our vocals to more closely reflect the mouth shapes, the facial expressions and tone of the animation in specific moments, and we would also discuss where the lip-sync and mouth shapes in the animation might be able to evolve in order to look like the characters are authentically singing.  As in all collaborative art forms, there is a lot of give and take, and if both departments are happy, you know you’ve really made something.

As you stepped into the world of KPop Demon Hunters, how familiar were you with K-pop?

I’d long been familiar with K-pop music and loved it, but I never imagined I would get to participate in creating K-pop songs. Culturally, I hadn’t attended K-pop concerts and didn’t fully understand the fan and idol culture. Learning about it was a fascinating and eye-opening experience. Now, after working closely with so many K-pop creators and performers, and through the overall process of making this film, I feel I truly understand it.

You worked with an extraordinary lineup of collaborators. What unique musical sensibilities did each of them bring to the soundtrack? On a personal and professional level, what did it mean to you to work with artists of this caliber?

Spring Asper assembled the list of collaborators. I want to give her a lot of credit for that. This simply could not have been done without her. The team was truly outstanding. We had The Black Label, who are legendary for what they create. We all know their vibe and their music, and they were perfect for HUNTR/X. We had Jenna and Steven Kirk who are the masterminds behind BTS’s Dynamite. More than that, they are some of the greatest pop songwriters of our day. They ended up doing the more epic, emotional songs like Free and What It Sounds Like. Also on our team was Lindgren, who wrote the awesome Takedown song. His vibes were perfect for that song. We also brought in Mark Sonnenblick, who is a long-time friend and collaborator of mine from the theatre world. He really understands narrative lyric writing making him a great addition to this team. 

Last, but most certainly not least, the star of this piece’s songwriting is EJAE. She was the one who developed the sound of HUNTR/X and wrote so many of the soundtrack’s unforgettable top lines. Not to mention, she sang all of Rumi’s vocals for the film. Collaborating with her was a life highlight. Then, having TWICE involved was a thrilling boost for all of us. The validity of a mega group like TWICE being involved meant we had something special.

Working with directors who understood K-pop from the inside, as both artists and fans, must have given the project a unique depth. How did their perspective guide or expand your own artistic decisions?

The directors played a major role in shaping the overall direction of the songs. Maggie knows and loves K-pop more than anyone I’ve met, serving as a constant barometer for what felt authentic and true to this film. Chris also has a strong musical background, which brought the songs to life in unique ways. It was a genuinely healthy collaboration: when all three of us were happy and aligned, we knew we had found something special.

‘Golden’ is both uplifting and introspective, tying deeply into the characters’ mission. How did you approach shaping a song that could reflect collective hope while also capturing more personal, isolating emotions?

We knew the song needed to be anthemic, uplifting, and joyful which was captured in the verses and the choruses, while also conveying the backstory of these three girls.

In the film’s plot there’s a lot riding on HUNTR/X’s success, so our goal was to create something that felt like a hot new single of the group. The key turned out to be crafting lyrics that let us step inside our hero’s mind, juxtaposing the group’s rise to fame with Rumi’s vulnerability, fragility, and self-doubt. This is when our protagonist’s curse is revealed: she is trapped in patterns.

The Saja Boys’ ‘Soda Pop’ introduces characters who are outwardly charming but secretly menacing. How did you approach composing a track that could function both as a catchy pop hit and a veiled warning of something darker beneath the surface? 

At first glance, the lyrics seem innocent, playful, and hyperbolic. We needed the music to portray these boys as charming, innocent, and entrancing who could somehow take over HUNTR/X.

The story and animation veil the warning of something darker beneath the surface. That contrast – the bright, peppy song against the looming danger of the Saja Boys’ rising popularity,  is what makes the number so fun and effective.

What was your favorite track from the album?

I can’t choose just one! I love all the writers and all the songs. They created something truly special; there aren’t many K-pop albums featuring such a caliber and variety of diverse artists who have never worked together before. So for them to come together and create this amazing soundtrack, I’m just proud of how each song turned out.

The blend of English and Korean lyrics feels seamless. Was that bilingual approach part of the vision from the outset, or did it emerge organically? 

Our director was keen on incorporating Korean, but also having English. Multilingualism was always the goal. We always knew the goal was to weave both languages wherever possible. At times we leaned into English for moments where clarity was crucial for the audience, while other lines just came alive in Korean.

Members of TWICE — Jeongyeon, Jihyo, and Chaeyoung — perform “Takedown,” a fiery diss track featured in KPop Demon Hunters. The song, which doubles as a warrior anthem for Rumi, Mira, and Zoey, also marked the first time the three TWICE members recorded together as a unit. (Photo: Netflix, used with permission)

The music has clearly struck a chord with listeners. What reactions have meant the most to you personally? 

Personally, K-pop fans loving the film has meant the most to me. They're seeing HUNTR/X and Saja Boys are true K-pop groups, and that is such an honor as someone who spent so long perfecting these songs with them in mind.   

There’s been speculation about a potential sequel. Looking back, were there any moments of doubt, or lessons you took from navigating such high expectations of K-pop? 

You never really know what you’re doing until you do it. I was always focused on creating songs that truly resonate with the K-pop audience, while also telling the story and staying in the film. It felt like an adventure and a risk; with films you never really know what you have until they’re released. When the film came out, it was like Christmas morning – I woke up and suddenly it was real, and everything just took off from there. I’d love to keep making music like this for the rest of my life.

Lastly, what has stayed with you most from the journey of shaping this soundtrack, and how has that experience defined success for you while influencing the way you approach your next creative chapter?

I think my takeaway is that one can create great songs that live as true universal pop songs while also creating songs that tell a story in a satisfying way. The interaction between these two elements can create something probably even deeper, more resonant, and more exciting than focusing on either one alone.