[Exclusive Interview] MOON SUA X SIYOON Redefine Their Artistry in Billlie's First Subunit Debut

Published 2 days ago• 9 minute read

From Billlie to a powerful subunit — MOON SUA and SIYOON open up about their bold new chapter, creative process, and what fans can expect in this exclusive interview.

Since their debut as members of the eclectic girl group Billlie in 2021, MOON SUA and SIYOON have consistently stood out for their lyrical prowess and dynamic stage presence. As rappers, singers, and songwriters, both artists have played a key role in shaping Billlie’s unique sound and storytelling, contributing to the group’s discography with thoughtful verses and distinctive flows. From the group’s first mini album, ‘The Billage of Perception: Chapter One,’ to their more recent releases, MOON SUA and SIYOON’s artistic voices have continued to evolve, gaining recognition for their authenticity and creativity.

Now, the duo steps into the spotlight as the first official sub-unit of Billlie. Debuting on April 7, 2025, with the digital single “Snap,” MOON SUA and SIYOON present a bold new chapter in their musical journey—one driven by their own vision. With lyrics co-written by the pair and a feature from rapper sokodomo, “Snap” delivers a sharp, confident sound that highlights their chemistry and creative synergy, showcasing their talents beyond the full group dynamic.

In this exclusive interview, we sit down with MOON SUA and SIYOON to talk about their sub-unit debut, the making of “Snap,” and how they’re redefining their artistry as a duo. From behind-the-scenes stories to personal insights, the two share what this moment means to them—and what fans can expect next.

Congratulations on your subunit debut! How did the idea for MOON SUA X SIYOON come about?

MOON SUA: We practiced together a lot since we were trainees. We used to say, “Let’s put on an amazing performance as main rappers someday,” I’m happy that we finally got the chance to do that.

SIYOON: Even before our debut, whenever I performed with MOON SUA, I could feel a special energy between us. Then we got this great opportunity, and now we debuted as a ‘main rapper’ duo that can show the special synergy.

What was your first reaction when you found out you’d be working together as a subunit?

MOON SUA: I love performing as a group Billlie, but I was excited to present the unit to our fans with SIYOON. Also, I kept thinking, “What kind of concept and genre should we show?” Since we’ve worked together for so long, I had no worries.

SIYOON: Exactly. In fact, I was relieved that my first unit was with MOON SUA! And since this is Billlie’s very first unit, I told myself, “We have to prepare properly and show everyone something amazing” (laughs).

How do your personalities and musical styles shape the subunit’s concept and sound?

MOON SUA: As “Main Rappers,” we focused on delivering a powerful and intense sound. We were able to work with a concept and genre that we felt best suited us, so the whole process was really enjoyable. The choreography also naturally came together in our unique style.

SIYOON: The song conveys messages about the struggles and reflections we encounter in life, as well as the growth that results from those experiences. We tried to express our boldest and most powerful energy through the music. The fencing scene in the music video is especially an important element that symbolically represents those emotions.

“SNAP (feat. sokodomo)” has such a bold, fresh energy. What was the message you wanted to express through the track?

SIYOON: This song goes beyond just success or failure; it’s about the ongoing journey of self-reflection and having an honest dialogue with your inner self. Since we took part in writing the lyrics, I wanted to bring out and express the most confident and empowered one inside of myself. I hope that every listener of this track can feel inspired to love themselves more and live with greater confidence.

What kind of mood or setting do you imagine for those listening to this song? Were there any songs or artists that inspired that vibe during your prep?

MOON SUA: When I listen to this song, I think “I’m the best” and “I want to be confident.” We’ve been inspired by many amazing senior artists who have shown incredible performances, but I hope that, for our fans, we can be that one unique unit that inspires them.

SIYOON: While preparing for “SNAP (feat. sokodomo),” I kept imagining myself on stage performing it. Since it’s a song I sing on stage, I wanted to fully understand the song and show.

The visuals for this release are super cool. Can you tell us more about the character or concept you portray?

MOON SUA: Since we have our own unique charm, we thought it would be really cool to showcase both of our individual charisma through the concept. We were also very actively giving opinions on hairstyles and outfits.

SIYOON: I think we gave lots of opinions on this unit concept. Since the choreography involves numerous hand movements, we thought that longer, more eye-catching nails would enhance the look, so we paid attention to those details as well. While our characters and concepts differ, we both sought to express our determination to overcome the challenges and moments we’ve faced in life and keep moving forward.

Can you walk us through the recording process for “SNAP (feat. sokodomo)”? Any fun or challenging moments?

MOON SUA: Since this was our first time as a unit, the recording process felt a bit challenging at first; there were more details to focus on (laughs). However, I was really reassured with SIYOON, and we were able to give each other detailed feedback and direction, which helped us complete the recording with a high level of quality.

SIYOON: Completing a song that used to be performed by seven members with just the two of us was more difficult than I expected. It made me focus more on expressing emotions in detail and studying myself. But because I was doing it with MOON SUA, every part of the process was enjoyable, and I feel like I grew a lot personally and professionally.

What’s something surprising you learned or bonded over while working so closely together on this subunit?

SIYOON: I’ve known this before, MOON SUA and I have quite different styles of writing rap lyrics. She tends to express her emotions directly, while I tend to use a lot of metaphors and symbols. I think it’s because her MBTI is S and I’m N (laughs). In particular, her diction and ability to convey emotions are charming. I fell for that charm even more through this promotion

MOON SUA: SIYOON’s lyrics are incredibly deep. At first, it might seem simple, but the more you think about it, the more you realize how delicate and thoughtful her expressions are. She’s not only an amazing rapper but also a great performer, so I learned and was inspired a lot while practicing with her. It feels like two people with similar yet different charms came together, learned more about each other, and grew even closer.

How did this subunit project push your growth, and how was it different from your experience with Billlie as a full group?

MOON SUA: When we perform as a group, a lot of things are divided among the members, but in a unit, it’s just the two of us leading the entire stage. So I thought more deeply about the overall quality from stage manners to performance to live vocals. It was an opportunity for me to grow and improve as an artist.

SIYOON: With group activities, we often focus on teamwork as a whole, but this time, I spent more time thinking about how to express “myself” and how the two of us could show our synergy on stage. It was a period of reflection and a chance to learn a lot about self-expression.

Are there any musical genres or themes you’d love to explore in future subunit releases?

MOON SUA: I want to challenge ourselves with all kinds of genres, without setting any limits. Above all, I’ve been interested in trying something more unique and upbeat. I think it could help us create a fresh new color that’s uniquely ours.

SIYOON: I felt that the hyper-hip-hop style we tried this time suited us well, so our goal is to keep building a signature sound that truly represents MOON SUA X SIYOON (Billlie). We want to explore different genres and reinterpret them in our style.

What are your goals and wishes for the rest of the year?

MOON SUA: Starting with this unit promotion, I want to show even more sides of myself this year, too. I hope to keep growing not just in performance but also musically, and ultimately become an artist that fans can always count on to deliver a great stage.

SIYOON: I think this unit will lead both of us to take on even more challenges moving forward. We’re also working hard to show great performances as a group, so you can definitely look forward to Billlie in 2025. Please look forward to both Billlie and MOON SUA X SIYOON (Billlie) (laughs)!

Lastly, please leave a message for fans reading this.

MOON SUA: To our Belllie’ve! Thank you so much for supporting our unit promotions. This was our very first time trying as a unit, and thanks to all of your encouragement, we were able to gain so much strength and confidence. I hope you enjoyed the new side of us we showed through “SNAP (feat. sokodomo).” We’ll continue to work hard to deliver even better performances. Thank you always!

SIYOON: We received so much love and support during this unit promotion, and I truly hope the messages we wanted to share reached all of you, Belllie’ve. As always, we’ll be back with more exciting activities, great music, and powerful performances.