Taesan

Started his trainee journey in Source Music after passing the audition at GoSilYong Academy in the fifth grade.

Later transferred to KOZ Entertainment, where he trained for about 6-7 years before debuting.

Showed a strong ability in composing and producing songs during his trainee years.

His family has been supportive of his long trainee journey, especially during his transition from Source Music to KOZ Entertainment.

All-rounder member known for his strong abilities in singing, rapping, and composing.

While no official position has been assigned, he often takes the intro part of the group's songs, setting the tone with his memorable and unique vocal color.

He is responsible for many of the chorus parts in the group's released tracks.

Has a strong imagination, often indulging in daydreams, which has helped him with his creative processes.

Very disciplined and maintains strict self-management, especially when it comes to his diet and exercise.

Known as one of the mentally strongest members, he's independent and prefers to solve problems on his own without relying on others.

Described by other members as calm and steady, with little emotional fluctuation, and he rarely gets nervous.

His favorite food is seafood and ramen, and he enjoys lemonade and other citrus drinks.

He prefers cakes like chocolate, cheese, and sweet potato, but isn't fond of whipped cream cakes.

He enjoys swimming, soccer, and indoor surfing, making him one of the more athletic members of the group.

Dislikes pineapple pizza, and isn't fond of chocolate or candy.

Avoids caffeine and energy drinks, and doesn't finish an entire can of soda.

He doesn't like eggplant or overly sweet desserts.

Known as one of the visual members of BOYNEXTDOOR alongside another member, Ihan, often recognized for his sharp jawline and trendy 'MZ-generation' looks.

Standing at 183 cm, he's the tallest member in the group with a slender physique and well-proportioned body.

Fans often compare his looks to a cat, and he has earned the nickname 'Ggamyang' for his feline-like features.