Rank: Sergeant. Before enlisting, she was an ordinary college student who worked hard at part-time jobs due to her family's modest financial situation. She enlisted after finishing the first semester of her sophomore year as an English Literature major at Danku University. She lives in a detached house in Sanggye 1-dong, Nowon-gu, Seoul. As the protagonist, she is treated as having the best visuals in the series.

Rank: Private. A clumsy soldier from the 893K class who is quite timid. During her time in the 1st Platoon, she struggled with slow work processing and a lack of situational awareness. Notably, after the 'Mess Hall Terror' incident where she accidentally overturned a meal tray on Jung Soo-ah, her position was changed to a cook in the Headquarters Platoon. (Actually, the incident was just a mistake by Lim Hyo-ju, and it could have been resolved smoothly with a bit of caution.)

Rank: Sergeant. She holds the same rank as Jung Soo-ah. While she is often overshadowed by other characters, Choi Ah-rang also has very handsome features. Her healthy copper-toned skin, voluminous body built through exercise, double-lidded eyes, and sharp nose are traits highly preferred in the West. She often has expressions where her eyes are wide open or she is laughing boisterously, and she is an excellent fighter.

When she first met Jung Soo-ah as a Private, she had a very short bob cut, but as time passed and she reached the rank of Sergeant, she settled into a bob that almost touches her shoulders. Uniquely, while her colleagues grew their hair out upon being promoted to Senior Sergeant, she has consistently maintained her short hair.

She has the most significant role among the three members of the 866th class in the 1st Platoon. She appeared as an antagonistic figure from her introduction until her exit as the leader of the 'Kku-eo' trio. Although her influence was weak because she was treated as a total failure (?), she lived straight enough to currently hold the rank of Sergeant alongside Jung Soo-ah.

Jung Soo-ah's immediate senior, she is a character with a chubby build and a unique way of speaking, often saying "Kku-eo." When she first transferred in, she failed to memorize the senior hierarchy and military codes, earning a reputation as a 'failure,' but she has now reached the rank of Sergeant.