We watched K-Pop Demon Hunters the other day. It’s very fun, I will add mine to the chorus of “watch it” voices. I probably wouldn’t have thought of it much past that, but Dani got the songs stuck in her head, and then John Scalzi (yes that John Scalzi) sent me down the rabbit-hole of vocal coaches reacting to Golden.
Then I learned about Kim Eun-jae. Kim was born in Korea in 1991. Starting in her teens, around 2003, she became a trainee for a major K-Pop entertainment agency, SM Entertainment.
Born in South Korea, Kim started out as a trainee for SM Entertainment for 10 years. When she wasn’t with SM, she was in the US to prioritize her education. She returned to South Korea to study at an international school and prepare for her debut.
She says she was like a beloved little sister to the members of Girls’ Generation. Born in Korea and raised in the U.S. during her early childhood, she returned to Korea for school and attended a foreign language school while preparing for debut. Ultimately, both her girl group and solo debut attempts fell through multiple times. Thanks to a contract that prioritized her education, she was still able to study music industry and psychology at New York University.
She spent 10 years training to be a K-Pop star while attending school in America. She returned to Korea, but all her attempts to debut fell through and she was told she was now too old.
“I went back to SM in my senior year of college, but our creative visions didn’t align, and I was older by then, so I never debuted. I was really depressed. That’s when I slowly started creating music on my own.”
She started songwriting for K-Pop groups and then TV before joining the songwriting staff at K-Pop Demon Hunters.
Her K-pop songwriting career officially began when a track she wrote about a fight with her boyfriend, titled Psycho, was selected as Red Velvet’s title track in 2019. At that point, she had written fewer than 10 songs and was virtually unknown, only having sung for a few drama soundtracks. She also received help from singer-songwriter Andrew Choi, who had been with SM. After a chance meeting, they became close, and he opened up collaborative opportunities for her like songwriting camps.
Kim transitioned to songwriting and producing. Her first big break came when she co-wrote the topline for “Psycho” for Red Velvet, which went on to be certified gold in the US. It led to more opportunities to work with SM Entertainment. In 2019, she was featured on the soundtrack of the K-drama Woman of 9.9 Billion.
EJAE joined the K-Pop Demon Hunters songwriting team in late 2020, during the early stages of production, thanks to an introduction from another colleague.
Tell me about that team of writers.
We had six to seven writers that we could task with different songs, some even with sections of songs, different elements. Some people wrote the topline and lyrics. Others created music production. We even brought in someone who specialized in more of a theater narrative lyric. Working with all those writers, I think, is what made this have this crazy alchemy. The number of writers on this film definitely exceeds the number of songwriters on most film musical projects — often it’s two people or one person.
We had the whole team at THEBLACKLABEL, including Teddy [Park], 24, Soulscape, Danny Chung. We had EJAE, who, early on, created the demos and helped us find the sound of HUNTR/X and she ended up writing top line and lyrics for a lot of songs. We had Steven Kirk and Jenna Andrews of BTS’ “Butter” and “Dynamite” fame, who wrote two of the songs. Lindgren wrote “Takedown,” and then Mark Sonnenblick we brought in to collaborate on lyrics focusing on story and character. We also used people top of the field in K-pop to mix and master the songs.
— Billboard, Executive music producer Ian Eisendrath
During the COVID-19 pandemic, Kim co-wrote “Drama” for aespa. She also helped co-produce the Girl Crush K-pop Vocals sample pack for producing k-pop songs. In 2022, she worked with Red Velvet again on the lead single “Birthday”.
As with her previous work for some of K-pop’s biggest girl groups (Red Velvet, aespa, NMIXX), songwriting was a team effort; EJAE bounced lyrics back and forth with Mark Sonnenblick, a composer with a background in narrative songwriting. But, whereas many of the writers on the project were used to cranking out demos in fast-paced environments like K-pop songwriting camps, this process was far more iterative — some songs took years to finalize.
Over the years of developing songs and sharing demos, the creators fell in love with her voice. Without even auditioning, she was offered the lead vocal role of Rumi, to sing the songs she had written and developed.
“Since I was recording the demos, the director got used to my voice, and I also started to feel like I could express my songs the best,” she said.
She was chosen as the singing voice for Rumi around 2023, when the song production was in full swing. Per director Maggie Kang’s vision, the songs featured high notes—but EJAE didn’t expect she’d be the one to sing them herself.
Among her collaborations with The Black Label, Your Idol—sung by the handsome grim reaper group “Saja Boys”—has become a sensation thanks to its captivating lyrics, such as ‘You know I’m the only one who will love your sins.’ EJAE shared, “I thought back to the bizarre and dark sides of idol culture, like how fans would throw trash at female trainees in front of the SM building.” She continued, “It also connects with the Christian taboo against idol worship. I drew inspiration from EXO’s MAMA and the hymns my father used to love.”
The theme song Golden is especially dear to her because it reflects her own story. “I remember crying while recording the demo. As a trainee, I felt intense pressure to hide my flaws and be perfect. As a songwriter, I was often overshadowed by famous names, which hurt me. But I found healing through relating to Rumi.”
“We can all relate to characters, whether they’re superheroes or not,” she says — though she has more in common with the leading HUNTR/X ladies than most. A former K-pop trainee of almost a decade, EJAE, like half-demon Rumi, knows “how it feels having to hide your insecurities.”
“‘Golden’ is a song that I put all my experience into, what I wanted to hear when I was training, because it’s not an easy industry,” she says. “It’s very competitive. Being perfect is such a big thing while training. So that part, feeling so broken inside, me not aligning and getting dropped, was part of it too. I brought that heartbreak I felt into the lyrics and when I’m singing.”
— Billboard, Executive music producer Ian Eisendrath
In 2025, Kim signed with Prescription Songs, an independent music publisher. In April of that year, it was announced that she would be featured on the soundtrack of the Netflix film KPop Demon Hunters. She also wrote several of the songs on the soundtrack. Director Maggie Kang attributed Kim’s demos as one of the reasons the film was greenlit; Kim explained she had co-written and recorded “most of the demos” for the film when the directors then asked her to be the official singing voice for the character Rumi.
Two decades since becoming a trainee, and a decade after being told she was too old to be a star, she is the lead singer/songwriter of HUNTR/X and is shattering records.
In addition to the film’s successful soundtrack, “Golden” attained individual commercial success worldwide, charting on various national record charts and garnering millions of streams. It reached number one on both the Billboard Global 200 and the Billboard Global Excl. US charts during the weeks of July 19, 2025, and August 2, 2025.
On July 3, 2025, the song reached number two on the US Spotify daily chart, with the BBC highlighting how it “surpass[ed] Blackpink as the highest-charting female K-pop group”. Five days later, on July 8, “Golden” topped the US Spotify daily chart, causing Huntr/x to become the first female K-pop group to have a song do so.
Netflix is planning to submit “Golden” for Oscars consideration. How does that make you feel?
That’s really gratifying because, out of any song in the film, that one had the most [options] written for that spot. It took a long, long time to find. It was literally the last song that we locked up, [we were] creating a new bridge for it in December and recording in January. What I’m excited about is that it’s doing it all. It’s a K-pop song, it’s a performance song, and then it’s got an internal monologue in the middle of it all. And people are just loving and embracing it as a pop song.
— Billboard, Executive music producer Ian Eisendrath
When we tracked her down, a reply came in straight from New York at 2 a.m. She was in the middle of working on another new song and began by saying, “I’ve had a lot of experiences where things didn’t go well no matter how hard I tried, so this overwhelming response feels surreal,” adding, “It was tough, but I really gave it my all.”
Even through the video screen, her sharp features, tall 174 cm frame, and confident, articulate speech leave a strong impression.
As a child, she dreamed of becoming the “Korean Beyoncé.” But she never imagined she’d debut as an “idol” in her thirties.
Referencing the lyric ‘I will no longer hide; I will shine,’ she said, “My mother always told me that words have power, and I hope this song gives hope to those who hear it.” She added, “I no longer have the desire to become a famous singer, but I want to win a Grammy for songwriting someday to show that Asians can succeed in the American music industry.”