Male / 28 years old Details: A former national archery representative who had to quit due to aftereffects from a car accident. He debuted through the idol survival program 'Idol Inc.' and serves as the leader of TeSTAR. Standing at 185cm, he is the second tallest in the group. He addresses members by their first names without surnames (e.g., Mundae, Sejin, Yujin). He has black hair with a subtle blue tint (styled in a half-up look) and dark eyes, possessing a generous and broad-minded personality. As a former athlete, he is quite muscular. His representative animal image in the group is a wolf. He is currently dating Mundae and they are engaged to be married.

Male / 28 years old Details: The same age as Ryu Cheongwoo, but at 177cm, he is the shortest member of the group. Although he has the earliest birthday, Cheongwoo is often mistaken for the eldest because of their height difference. He has brown eyes and brown hair. He is a textbook tsundere. He addresses everyone using their full names including surnames. His representative animal image is a hamster.

Male / 26 years old Standing at 187cm, he is the tallest member. He has brown eyes and brown hair and is the group's mood maker/comedian. He has a habit of calling Mundae 'Mundae-Mundae' and Ahyeon 'Ahyeon-Ahyeon'. He playfully calls Cheongwoo and Bae Sejin 'Cheongwoo-hyeongnim' or 'Sejin-hyeongnim', while addressing Cha Yujin and Kim Raebin by their first names. His representative animal image is a bear.

Male / 26 years old The most handsome member, though he is quite timid. He has a slight stutter, though it has improved significantly. He has light brown hair and eyes. His representative animal image is a fawn.

Male / 24 years old Hails from California; his legal name is Eugene Ignacio Cha. Being a 'Cali boy,' his Korean is a bit awkward. He speaks a mix of Korean and English. He has red hair and yellow eyes. He is best friends with Kim Raebin, and their daily routine involves bickering (e.g., "Kim Raebin, you dummy!!"). His representative animal image is a cat (though he insists he is a tiger). He is part of TeSTAR's maknae line.

Male / 24 years old He might look like a delinquent at first glance, but he is actually a very polite 'Confucian boy.' He uses formal speech patterns like "Understood!" or "As expected, Mundae-hyeongnim's vocal skills are incredible!" He handles producing and is very satisfied with Mundae's vocals. He has purplish-black hair and purple eyes. His chemistry with Cha Yujin while shouting "Cha Yujin, you idiot!!" is part of his charm. His representative animal image is a rabbit.