Who Are the CORTIS Members? Meet BigHit Music’s Rising K-Pop Stars Taking the World by Storm

Every generation of K-pop produces a group that feels genuinely different — one whose arrival makes fans and industry veterans alike stop and pay attention. In 2025, that group was CORTIS. Since the moment CORTIS members stepped onto the global stage, they have done nothing but break records, defy expectations, and redefine what it means to be a K-pop act in the modern era. BigHit Music’s third group after BTS and Tomorrow X Together, CORTIS debuted on August 18, 2025, with the single “What You Want” and went on to release their first extended play, Color Outside the Lines, which debuted at number 15 on the Billboard 200 — the second-highest entry for a K-pop act’s debut album.

That is not a rookie milestone. That is a statement.

But who exactly are the people behind this phenomenon? What makes each CORTIS member unique, and why has the global K-pop community embraced them so passionately in such a short time? This article answers every one of those questions — with fully verified, up-to-date information on all five members: Martin, James, Juhoon, Seonghyeon, and Keonho. Whether you are a dedicated COER (the official fandom name) or someone who just discovered the group, this is your definitive guide.

What Is CORTIS? The Group at a Glance

Before we meet the members individually, it helps to understand what CORTIS is and what makes them distinct in the crowded landscape of fifth-generation K-pop.

The Name and the Concept

The group name CORTIS is short for COLOR OUTSIDE THE LINES (선 밖에 색칠하다), symbolizing the idea of “thinking freely and breaking free from the world’s standards.” It is not just a catchy phrase — it is the operating philosophy of everything the group creates, from their music to their visuals to the way they interact with fans.

CORTIS is strategically positioned as a “young creator crew” rather than a traditional idol group, with all members actively involved in songwriting, choreography, and video production. This is what sets them apart in a genre where self-production at the debut level remains genuinely rare.

The Agency Behind Them

CORTIS is a five-member K-pop group under BigHit Music, a subsidiary of HYBE — the label that launched BTS and Tomorrow X Together. Their debut in 2025 marked BigHit’s first new boy group in six years following TXT. In the United States, they are represented by Republic Records.

Fandom Name

CORTIS’s official fandom name is COER (코어). The name brings together “COR” from CORTIS and “~ER” (those who stand together), while also echoing “CORE” — symbolizing the fans who support CORTIS with the deepest love and passion and who will “color outside the lines” together with them.

Complete CORTIS Members Profile — Who Are They?

Here is everything you need to know about each of the five CORTIS members, verified from official and credible sources.

1. Martin — The Leader

Martin was born in Songpa-gu, Seoul, South Korea, and lived for a time in Ottawa, Canada. His father is Canadian and his mother is Korean.

Martin is the group’s confirmed leader — a role officially confirmed on Weverse — and is also the tallest member of the group.

Even before CORTIS debuted, Martin had already made his mark within the HYBE ecosystem. As a prolific songwriter and producer, he has credits on tracks for senior HYBE acts including TXT (“Deja Vu,” “Miracle,” “Beautiful Strangers”), ILLIT (“Magnetic”), LE SSERAFIM (“Pierrot”), and ENHYPEN (“Outside”).

He helped produce all five tracks on CORTIS’s debut EP Color Outside the Lines and contributed to the choreography for their pre-debut song “GO!”

One remarkable pre-debut detail that has captivated fans: Martin was part of the children’s choir at the 2018 PyeongChang Winter Olympics and served as a flag bearer for Iceland.

Fun Facts: Martin is a dog person who loves the color orange. His playlist includes Mac Miller and Tyler, the Creator, and his role models are BTS’s RM and Justin Bieber.

2. James — The Multilingual All-Rounder

Zhao Yufan, professionally known as James, is a multilingual Thai-Hong Kongese singer, songwriter, and choreographer under BigHit Music who officially debuted as the eldest member of CORTIS on August 18, 2025.

He was born in Hong Kong but grew up in Taiwan and is of mixed descent — Thai on his mother’s side and Chinese on his father’s. He speaks five languages: English, Chinese, Thai, Korean, and Japanese.

James first gained prominence as a member of the pre-debut project Trainee A. Despite the group’s failure to debut, James remained with BigHit and continued to develop his craft.

His production resume before CORTIS’s debut is staggering. James has contributed as a producer to TXT’s “Deja Vu” and “Miracle”, as well as ILLIT’s “Magnetic”. He even performed as a backup dancer alongside Jungkook during the “Seven” promotions.

In CORTIS’s debut year, he has already seen significant acclaim, with the group winning the Global Rookie Award at the 2025 TikTok Awards Korea and achieving over 200 million streams on their debut EP.

Fun Facts: Before focusing on music, James trained in taekwondo and ice hockey, even competing at the Hong Kong level. He also enjoys playing piano.

3. Juhoon — The Visual with Depth

Juhoon was born in Seoul, South Korea, and is an only child. His family has a pet turtle named Choco.

Before his idol career, Juhoon was a child model and an active athlete, playing basketball for a youth team with Samsung Thunders and soccer with AAFC FC Seoul Chungam. His childhood dream was to become a soccer player.

His background in modeling is impressively documented. Juhoon appeared in music videos including VIXX’s “Scientist”, Zion.T’s “Hello Tutorial”, and multiple MeloMance videos including “Tale”, “You & I”, and “Festival”.

He studied at Sangmyung University Teacher’s College Experimental Elementary School and Young Hoon International Middle School, the latter giving him strong English fluency.

Juhoon contributed to four songs on CORTIS’s debut EP Color Outside the Lines: “GO!”, “What You Want,” “FaSHioN,” and “JoyRide.” He also helped with choreography for “GO!”

Fun Facts: Juhoon’s audition song was “Slow Dancing” by BTS V. He is known among members for asking every day, “What do you guys want to eat?” — and according to Martin, he eats the most in the group.

4. Seonghyeon — The Creative Powerhouse

Seonghyeon was born in Seo-gu, Daejeon, South Korea, and has a younger sister born in 2012.

Seonghyeon began his training at the young age of 13 and trained for approximately five years before debuting. He is described as a “creative powerhouse” with outstanding talents in singing and dancing. During his training period, he worked on over 100 tracks, demonstrating his prolific output as a lyricist.

Seonghyeon is described as the group’s main “Topliner,” meaning he writes the core melodies — the catchy, memorable tunes — that become the backbone of CORTIS’s best songs.

He ranked first among BigHit Music trainees at a monthly evaluation and holds a 2nd dan in taekwondo and a black belt in hapkido. He has also earned two Book Club awards for reading over 100 books.

Despite his calm demeanor, Seonghyeon is the type who gives everything 100%, once performing with an injured finger and wearing a protector to avoid missing the stage.

Fun Facts: Seonghyeon enjoys watching movies and dramas, skateboarding, cycling, and playing basketball. He dislikes mint chocolate and loves acai bowls. His favorite color is green.

5. Keonho — The Maknae and “5th Gen It Boy”

Keonho was born in Pajang-dong, Jangan-gu, Suwon, Gyeonggi-do, South Korea. He has an older sister and his family has a puppy named Cookie.

Keonho was previously a competitive swimmer, noted for his skills and multiple victories at meets, before choosing to join BigHit. He values manners and discipline, which he credits to the influence of his swimming coach.

Keonho dropped out of Chonggye Middle School to dedicate himself fully to training — a decision that reflects the extraordinary level of commitment required to debut under one of K-pop’s most prestigious labels.

Within CORTIS, Keonho plays a major role in creating the group’s music videos, and fans have already dubbed him the “5th Gen It Boy” for his magnetic screen presence.

He contributed to four songs on the debut EP and played a key role in the production of “JoyRide.” He also participated in choreography for “GO!”

Fun Facts: Keonho’s audition song was “Dynamite” by BTS. His favorite CORTIS music video is “Lullaby” because, as he put it, “it just felt like we were hanging out together.”  

Quick Comparison Table — All CORTIS Members at a Glance

CORTIS’s Music and Achievements

Debut Discography

CORTIS wasted no time establishing their sound. On August 11, 2025, CORTIS released their pre-debut single “GO!”, with all members contributing to the songwriting and composition, while the accompanying music video was filmed in Los Angeles. They officially debuted with the single “What You Want,” featuring choreography performed on treadmills.

Four days later, the group released an English version of the song featuring American singer Teezo Touchdown, and performed the track with him on Mnet’s M Countdown.

They released their debut EP, Color Outside the Lines, on September 8, accompanied by the single “FaSHioN.” The music video, filmed in Christchurch, New Zealand, accumulated one million views within 12 hours.

Record-Breaking Numbers

The numbers CORTIS put up in their debut year are historic by any standard:

Color Outside the Lines debuted at number 15 on the Billboard 200 — the second-highest entry for a K-pop act’s debut album — and set records for first-day sales, reached 200 million streams in record time for a rookie group, and surpassed two million in cumulative album sales.

Their debut EP sold approximately 250,000 copies on its first day, setting a new record for first-day sales among 2025 debut acts, with approximately 430,000 first-week copies sold in Korea — the highest first-week numbers among 2025 rookies.  

CORTIS were also the first Korean boy band to perform at a 2026 NBA All-Star Game.

Awards

In just their first months as a group, CORTIS accumulated a remarkable number of accolades:

They won several awards at the 10th Asia Artist Awards, the 2025 MAMA Awards — including Best New Artist — and the 40th Golden Disc Awards, where they won Rookie Artist of the Year.

CORTIS’s Global Fanbase and Cultural Impact

How the World Discovered CORTIS

In December 2025, CORTIS were announced as headliners for the NBA Crossover concert series in February 2026, alongside Ludacris and Shaboozey. That same month, they performed at Tokyo National Stadium for KBS2’s 2025 Music Bank Global Festival in Japan, performing “What You Want” and a cover of BTS’s “Mic Drop.”

Their global crossover appeal has been recognized by major international publications. The Hollywood Reporter observed that although songs such as “GO!” and “What You Want” were sonically different, both suited the group’s artistic vision, concluding that “Cortis seems focused on one thing more than making exactly the kind of music expected of them: authenticity.”

Color Outside the Lines was included on the list of the 15 Best Non-English Albums of 2025 by Teen Vogue.

What Sets CORTIS Apart

In a generation filled with talented K-pop acts, CORTIS stands out for one reason above all others: authenticity. Members received personal advice from their senior labelmates in BTS and TXT. BTS advised them to “do well by the people that you’re working with.” Juhoon noted that advice from BTS helped him understand that debut is just the beginning, and that it is more important to “show improvement and keep evolving” than to be perfect from the start.

American singer-songwriter Ryan Tedder — who has worked with BLACKPINK, Taylor Swift, Demi Lovato, and Beyoncé — served as a producer for the group. Yet despite this high-profile industry involvement, every CORTIS member has co-writing credits on their debut EP — something that is genuinely rare and speaks to the depth of their creative involvement.  

Upcoming Projects: What’s Next for CORTIS?

The CORTIS story is still being written — and 2026 is shaping up to be an even bigger year.

CORTIS is set to release their second EP, GREENGREEN, on May 4, 2026. The second EP includes new tracks such as “TNT,” “REDRED,” “ACAI,” “YOUNGCREATORCREW,” and “Wassup,” all of which feature writing and composing credits from the members.  

With their NBA All-Star performance already in the books and a global fanbase growing by the day, CORTIS appears to be building toward the kind of sustained international presence that only a handful of K-pop acts have achieved.

Frequently Asked Questions About CORTIS Members

How many members are in CORTIS?

CORTIS is a five-member South Korean boy group. The members are Martin, James, Juhoon, Seonghyeon, and Keonho.

When did CORTIS debut?

CORTIS debuted on August 18, 2025, with the digital single “What You Want.”  

What does the name CORTIS mean?

CORTIS is an acronym for COLOR OUTSIDE THE LINES, which means “to think freely and break free from the world’s standards.” The name is derived from six irregular letters taken from the full phrase.  

Who is the oldest CORTIS member?

James (born October 14, 2005) is the oldest member of CORTIS. At the time of their debut, all members were teenagers, with an average age of 17. James was the only adult at debut.

Who is the youngest CORTIS member?

Keonho (born February 14, 2009) is the youngest member, or maknae, of CORTIS.

What agency manages CORTIS?

CORTIS is managed by BigHit Music, a subsidiary of HYBE — the same label behind BTS and Tomorrow X Together.

Where can I follow CORTIS on social media?

CORTIS is active across multiple platforms: Instagram (@cortis), TikTok (@cortis_bighit), X/Twitter (@cortis_bighit), YouTube (CORTIS), and Weverse (CORTIS).  

What is the CORTIS fandom name?

The official CORTIS fandom name is COER (코어), representing the fans who are the “core driving force” behind CORTIS.

Final Thoughts — Why CORTIS Members Deserve Your Attention Right Now

CORTIS did not arrive quietly. In less than a year, these five young men — Martin, James, Juhoon, Seonghyeon, and Keonho — have broken Billboard records, performed at the NBA All-Star Game, earned major industry awards, and built a fiercely devoted global fanbase. All of this as teenagers.

What makes their story compelling is not just the numbers, impressive as they are. It is the way they have achieved those numbers — by being genuinely, consistently themselves. They write their own music, choreograph their own performances, direct their own videos, and speak honestly about their creative process. In a genre that can sometimes feel polished to the point of distance, CORTIS feels refreshingly close.

As The Korea Herald observed, CORTIS has crafted “a distinct identity for themselves through fresh sounds and performances that defy expectations” — and they have done so while redefining creativity within the entire K-pop industry.

Whether you have been following them since “GO!” dropped or you are only just discovering them now, one thing is certain: the CORTIS story is one of the most exciting ongoing narratives in Korean entertainment today.