It’s not an exaggeration to say that “Golden” from KPop Demon Hunters is the “Let It Go” of the 2020s: a song originally written by a movie musical that has gone viral. It now has a Grammy Award nomination for Song of the Year and just won the Critics Choice Award for Best Song. And just like “Let It Go,” “We Don’t Talk About Bruno” or other ear-worm songs from screen musicals, “Golden” was co-written by a musical theatre songwriter.
Mark Sonnenblick first got the call from the movie’s executive music producer Ian Eisendrath (The Heart, Come From Away) in 2023 to come work on a film about a group of pop stars who use the power of their voices to rid the world of demons. In other words: a movie musical.
As Sonnenblick, who is also a lyricist on the current Devil Wears Prada musical in the West End, explains: “This was the chance to really make pop songs, but be very, very deliberate about—basically every line has a function in the story.” Sonnenblick was one in an expansive team of songwriters, including Ejae (the singing voice of main character Rumi), whose job it was to “push each other to be like, ‘Okay, this is a musical. But also every one of these songs needs to be an absolute banger that can stand on its own, because that's who the characters are. They are the biggest pop stars in the world, so the songs are helping to tell that story.”
KPop Demon Hunters has become such a surprise hit for Netflix and Sony Animation that a sequel and stage musical is now on the table. Sonnenblick is especially supportive of KPop Demon Hunters the stage musical: “These songs are written like musical theatre songs, even if they don't always sound that way, and they're very functional. So, it’d be an amazing musical, just putting that out there!” The team also wrote over 30 songs, many of which ended up on the cutting room floor, so there’s plenty of material to pull from.
But while we all wait with baited breath for KPop Demon Hunters on Broadway, Sonnenblick has broken down the construction of every song he helped write for the film track-by-track style, including “Golden,” “How It’s Done,” “Free,” “What It Sounds Like,” and many more—truly showing Kpop and musical fans alike how it’s “done done done.”
“Hunter’s Mantra”
Sonnenblick: Ejae and I did this with Daniel Rojas—it’s split up throughout the film. Ejae sings this bridge that's in Korean, which you hear in the opening of the movie. Then later on in flashback, you hear Rumi and Celine (Lea Salonga!) sing: “We are hunters, voices strong / Slaying demons with our song / Fix the world and make it right / When darkness finally meets the light.”
The idea was to write a mantra that sets up the hunters’ values, the thing that Rumi and the girls feel like they are chasing, their duty and their obligation. But story wise, it also needed to be a little bit toxic for them in the sense that they are striving for perfection—there's all this pressure to, in Rumi's case, literally save the world with her voice. And as her voice goes away, “We are hunters, voices strong” echoes painfully. Like, how can I be a hunter without my voice? It's so key to who I am.
The other anchor line was “when darkness finally meets the light,” which I pitched as this idea that maybe there’s part of the mantra they are misinterpreting the entire movie. I love when there are prophecies or riddles that characters think they understand but only after they have their personal revelation does the true meaning become clear. This plot thread ended up being a little less present in the final cut of the film but thinking that in the girls’ mind, the line means “light is going to banish darkness. Light is going to push darkness away with the Golden Honmoon.” But actually at the end, we realize “when darkness finally meets the light” means showing a part of yourself that you've hidden away.
The film is going to be Rumi realizing that: accepting who she is, vulnerability between people, that’s actually what’s going to unite everybody.
“How It’s Done”
This was one of the hardest songs to write. It’s the opening of a musical; this is the hook. Especially with something like Netflix, where you're receiving it on a streaming platform, you could just turn to something else; in the first 10 minutes, someone keeps watching or they don't. So, getting this right was really important.
I did three versions with Ejae; this was the third version. Black Label—who we did “How It’s Done,” “Golden,” and “Your Idol” with, this amazing Korean production team behind Blackpink and so many other groups—they delivered a couple different track options. And Maggie Kang and Chris Appelhans, our brilliant directors, knew that they wanted some traditional Korean instruments to connect Huntrix to their legacy as hunters. So that's where the synth line comes from. And this was a track where we and Ian were like, “This is great, this feels right.”
What was cool about this song was the whole thing was basically storyboarded before we wrote the lyrics. So, we got to write to the visual. We know Huntrix are fighting the demons in a plane. We know they're going to fall out of the plane and do their makeup. And then they're gonna land in the stadium and then continue performing the song for the crowd. Ejae brought in pieces of an older opening she and Daniel Rojas wrote called “Bite Back.” And we loved this vocal hook she did, very Blackpink, of “dun dun dun.”
So then what’s fun in terms of the storytelling part is like, “Great, we have dun dun dun. That's a catchy hook, but what work does the song title actually need to do?” If we called it, “We Kill Demons,” that would work great for the fight on the plane, but it's not going to work when they're singing to the fans. Like in musical theatre, you need to find a title that evolves and makes sense across every piece of the action. So dun dun dun became, “How it’s done done done. We're going to show these demons how we kill them. Then we're going to show these fans how we're the greatest pop group in the world.” And again, we have all this animation to reference. So like the, “heels, nails, blade, mascara / Fit check for my napalm era”—that was literally written to the storyboard where they're doing their makeup. Also shout out to Danny Chung, who we wrote the raps in this song with. “Something about when you come for the crown / That's so humbling, huh”—that whole really fast section was entirely Danny. He's with Black Label, he voices Baby Saja, he’s incredible.
And then the last piece of it was the bridge. As the movie evolved, the directors wanted to get to know the girls more in this song, and we needed to hear Rumi really sing—hear the power of what her voice does before she starts to lose it. So Ian pitched a bridge that lays out the power of Rumi's voice and of Huntrix; she’ll sing SO high. Ejae still didn't know she was going to have to be singing these notes live. And we’d already written the mantra with “when darkness finally meets the light.” So let's add that to the bridge, let's set up the lore; that's what they think they're chasing. That's what their voices are going to do. And then instead of bringing back the synth hook from the first chorus, in this chorus we’ll drop in Mira and Zoey’s raps to get a little sense of who they each are.
Like any great opening number, you're not only learning about the characters, but you're learning how they speak. You’re learning the energy of this musical and this movie. If everyone—writers, filmmakers, music team—hadn’t pushed for this song to be what it was, I think a lot of people would have been like, “oh, okay,” And not kept watching.
“Jinu’s Lament”
This is such a short little thing but I love it. Classic musical theatre moment—a song has to do six things in 12 lines. We need some literal exposition: Gwi-Ma is the demon king, he eats souls, the hunters are winning and he is starving. We need to introduce Jinu’s attitude and vibe: he’s slick, he’s smart, he’s a wise ass. Maggie told me it was her husband’s idea to introduce Jinu with a song (thanks Rad!), but if he sings right away it kills his coolness. Still, the moment needs to demonstrate that he’s a great singer because it’s key to his entire character. So that’s why the lament landed in between—some spoken lines, which make the exposition easier to write anyway, and then a little sung coda that hammers home the theme and shows off his pipes. Daniel Rojas wrote the chilly bipa instrumental backing for this one and I swear you can somehow hear Jinu’s attitude in that too!
“Golden”
This was the last song that we wrote. By then we had our standard songwriting process down. Black Label sends a track, and everyone gets excited about the track. Then the melody, the lyrics, the story, the structure—that's kind of a back and forth with Ejae, me, Ian, and the filmmakers. I worked on two totally different versions of “Golden” with different songwriting teams. There were also three or four other versions. It's tricky because this is the monster hit single Huntrix releases into the world.
But it’s also such a key moment for us to get on board with Rumi and her journey. That's why you have an “I want” song. A moment of vulnerability and yearning from the main character that anyone can relate to. But Rumi is so strong and powerful—how do you let her be vulnerable and not undermine what is great about the character?
“Golden,” before this final version, was basically just a pop song all the way through. Maggie and Chris knew they wanted the word gold or golden to be a part of it. They knew it needed a superhuman high note for Rumi to sing. They called it the “false victory” song, like Huntrix is almost there, they're pushing towards this kind of perfection like in the mantra. But it’s a perfection that they cannot reach. So that was always a part of other song versions. But there was not a section where Rumi got emotional.
And then there was a real breakthrough—I honestly don't know if it was Ian or Maggie or Chris or Michelle Wong, our amazing producer. Someone suggested that the bridge of the song can be Rumi's vulnerable moment. The scene of her in the dressing room with her patterns always existed; it just wasn’t musicalized. But what if it was? And Ian and I, musical theatre nerds that we are, were like—without breaking a pop form, here’s a way to get “I Want” lyrics that come directly from Rumi’s heart, the part she doesn’t want anyone to hear.
And suddenly the whole structure became clear. The first verse/pre-chorus can be the hit single they’re releasing—perfect, pre-recorded, exactly the way they want to be heard. Then in the bridge we’re going to learn Rumi’s secret, the irony that that pop sheen “no more hiding” for her is a lie. But she so desperately wants it to be true, launching her journey. And then the final chorus will be live during the rehearsal, now that we know the truth, and Rumi won’t be able to sing the perfect note we already heard in the first chorus. I feel like so much of musical theatre songwriting is figuring out how to map song structure onto story beats. And in “Golden,” we have pop song sections that also evolve dramatically, that lay out Rumi’s desire and her struggle and end with the problem she has to solve for the rest of the movie.
And really the structure of “Golden” is so strange for as much of a banger as it is. You have two verses that never repeat because you're getting the girls’ backstory: the pressure that Rumi feels inheriting her destiny from her mother, Zoey pulled between two worlds, Mira who was this rebel kid. They all have found their outlet in this group. Then in the bridge you go from a pop song that exists in-universe to something that is non-diegetic, and then we do a big final chorus that gets interrupted—structurally dictated 100 percent by the story needs. But, at the end of the day, it had to pass muster as a pop song. Aside from Ejae casually writing one of the most iconic melodies ever, so much credit goes to her, Rei Ami and Audrey’s insane vocal performances! And Ian’s genius for balancing pop and character in the vocal coaching…brilliance all around.
“Free”
“Free” was the first song that I worked on. Stephen Kirk and Jenna Andrews, who I wrote it with, had a draft of this song that was musically stunning. They had a verse and chorus. And I came in and worked with them to develop it into what the filmmakers needed.
What was tricky about “Free,” and this is also the thing about “Golden,” is this is a moment in Rumi's journey where the lyrics talk about something seemingly good, but actually they still can't be right. “Free” cannot be the answer in the way that “Golden” can't be the answer. If “No more hiding / Now I'm shining” were true when Rumi sings it, the movie would be done 20 minutes in.
In “Free,” Rumi is like, “Jinu, if we lean into our connection and trust each other, we can fix what’s wrong with us. We can find a way to be free of our darkness.” And that is a beautiful sentiment, but in the story it’s also offbase because Rumi ultimately needs to embrace her patterns, not escape them. So, there was a calibration of: How do you write something that rings true and can stand alone in a pop song but not let it step on Rumi’s realization later in the story? That’s one challenge in a musical—each song is its own thing but also part of something bigger.
It was also important to Maggie and Chris that this is a moment of connection but not some big love song. Here are two damaged people who hate parts of themselves, trying to understand why vulnerability with each other is helping. So the lyrics are not just, “We're together, everything is great. I can't wait to spend my life with you.” It’s this in-between: “I can't figure this out, it doesn't make sense, I don't know why. But being with you, something is changing for the better.” I love where the lyrics landed and Ejae and Andrew Choi, who sings Jinu, absolutely crushed that raw emotion in their vocals.
This was a song where some storyboarding existed before writing too. “Let the past be the past till it's weightless” came from concept art that had them flying in this sequence. And the bridge! That was the first new piece of music I got to be a part of in the movie. Jenna and Stephen came back with this crazy top line, and it was so emotional. Then the job becomes writing a lyric so simple it stays out of the way of the melody: “So take my hand, it's open.”
Also gotta say, for all the rewrites this song went through, the “between imposter and this monster” line was in Stephen and Jenna’s very first draft and it’s one of my favorite lyrics in the film.
“Your Idol”
“Your Idol” was the second song Ejae and I did with The Black Label. Before any music happened, it was called “Saja Boys Black Hat Song” because they knew what the look was going to be. When K-pop groups come out with different albums or different singles, they’re not always maintaining some established brand. A lot of times, their entire vibe can change. So, the directors’ idea was a riff on that: “Okay, we're gonna get the bubbly ‘Soda Pop’ Saja Boys. And now they've gone to the demon look for their latest single.” Which is totally something a real K-pop group would do. But obviously in the movie, the demon look is just their real demon form!
The song started with Black Label delivering an instrumental track that fit the vibe Maggie and Chris were going for. We knew we wanted it to be choral, demonic, the villain song. And lyrically the theme needed to get at the heart of the entire movie. You have Huntrix, whose job is to connect people through music. The Honmoon is strengthened when fans unite around the songs they're singing. It's a way to go: We are together, we are seen, we are part of something bigger than ourselves.
And what Saja Boys and Gwi-Ma want to do is the opposite. It’s another side of music: headphones on, on the train, ignore the world, lock in on a singer, a song—this more toxic, isolating relationship with music. Listen to the voice in your head, don’t trust your community, no one else is going to love you, only I'm going to love you. The whole movie is about the power of music, which is partly why I think it works so well. And this song speaks directly to that theme.
The directors gave us, like, two pages of what they wanted the song to be about. Ejae pretty quickly went, “I think there's something here with idol.” That checked all the boxes: We have the demon god, false worship, K-pop idols. And because the story engine is happening more through the visuals, the lyrics have more room to riff on the theme. And they’re some of my favorites: “Anytime it hurts, play another verse / I can be your sanctuary.” This idea of music as a home but an isolating one. “I'm the only one who'll ever love your sins.” It sounds comforting but it’s so dark.
“Thank you for the pain, because it’s got me going viral.” So this was less about, “Hey, here's all the story beats we need to hit.” And more like, let’s just have a couple of fire lines and write a song where a listener would think maybe the message is good. But then, in context, the Saja Boys are literally stealing everybody's souls.
The bridge where they’re “living in your mind.” We did a bunch of different versions of that. At one point, Gwi-Ma was going to sing part of the song. The filmmakers asked for something like “Thriller,” and he came out and sort of spoke, “What a crowd! Place is packed / Hope you like the final act / Sing along, let’s see those hands / We really really love our fans.” Vincent Price sort of thing. The “living in your mind now” line was for Gwi-Ma too initially. And then it was like, what are we doing? Gwi-Ma definitely shouldn't sing.
I love the animation so much in this song. Every song is its own music video; the filmmakers and artists have a different set piece and concept for each one, like in a musical. And seeing the final “Your Idol” animated completely blew me away. So hot. So iconic.
“What It Sounds Like”
“What It Sounds Like” is the other song I wrote with Stephen and Jenna. This took more than a year; it was the hardest one long-term to crack, because it is so story-based and literally the climax of the movie. It’s uniting the story thematically and doing it through Rumi’s words and actions, the connection between her and the other girls and the crowd. Unlike “Free,” the three of us built WISL from the ground up. So, it started with me sending a bunch of potential hooks, lyric ideas, things to maybe start to center the song around. Initially, it seemed what was really going to drive this end scene was this idea that they've been looking for a Golden Honmoon but instead they create a Honmoon more beautiful and multi-faceted than they ever imagined. So, I pitched “Kaleidoscope,” inspired by all these colors and broken elements combining into something gorgeous.
The original verses were very different than what ended up in the movie, but it was still coming from a place of, “I thought I had to be perfect. Golden for the people around me. But my true friends will love my imperfections. They can be strengths if I learn to live without shame.” That message resonated so deeply with me from the moment I was pitched the project, absolutely my personal way into Rumi’s story. And I wanted to bring that emotional release home. I was thinking about “Cut to the Feeling,” the Carly Rae Jepsen song—I felt like we needed a chorus like that. So I kind of mocked up this “I broke into a million pieces, and I can't go back” idea. And the lyrics, “all the colors stuck inside my head” etc. still centered around this kaleidoscope imagery. Anyway, the filmmakers went away, they storyboarded it and brought it back. But it just wasn’t hitting. It felt too basic. “Kaleidoscope” isn’t connected to the rest of the movie and this song is the culmination. It's not like Rumi's mom left her a toy kaleidoscope. So it’s a word you're introducing very late, a random image. And the Honmoon being multicolored isn’t actually what the moment is about. It's about Rumi finally being honest, connecting with the girls, singing in a new way with Huntrix. This is a song about their voices combining.
As that became clearer, I pitched a rewrite called “The Song We Sound Like.” Because Huntrix has been trying to write this song the whole time. They think it's going to be “Golden.” Then “Takedown.” And finally in this moment, they’re able to find the song they sound like because they’re being honest. That's when the verses started to lock in. What was cool is by then, the filmmakers had developed more of the storyboard so we could start writing to the animation. There's some video somewhere of me in a very bad, auto-tuned way singing over the boards, making sure the lyrics are hitting moment to moment. The hook eventually became “What We Sound Like,” at which point Stephen said, “I can’t fully explain why, but it's actually poppier to do ‘What It Sounds Like.’” Which is the intangible magic of collaboration.
The last piece (surprise surprise) was the bridge, as is so often the case because it’s a wild card section. What is the song missing? Put it in the bridge. We had some versions with a “Free” reprise in it: Rumi calls out to Jinu to get him to switch sides. Jinu even did a whole rap at one point; they sang “free, free” together as the crowd sings the “What It Sounds Like” chorus. But it was too focused on Rujinu instead of the girls and didn’t land Jinu’s arc in a satisfying way. Then the filmmakers added his sacrifice in, absolutely destroying me and the entire world…a spoken bridge. As cool as the “Free” reprise was musically, they ended up with a brilliant and better story.
But we did still want to find a way to reprise something. Musical theatre reprise come on! As the focus became more about the three girls coming together, and the way that vulnerability not perfection is what connects everyone, we were like, “What is the song that the crowd could sing together?” By then, Ejae and I had written “Golden,” so it was like, the crowd's gonna know that song. It’s the Huntrix hit single. They don't sing the lyrics but you hear that melody in the build.
Every time I watch this song, the animation, Stephen and Ian’s production, Ejae’s vocal arrangements, the girls’ singing…I’m wrecked. The climax is such a hybrid of filmmaking and songwriting and storytelling. Which is what excites me as a theatre writer: creating songs in collaboration with other artists that could only be written for this moment in the story, for this character. With KPDH, it just so happened that these songs are also pop songs that people wanted to listen to.
