Male (One of the most popular boys in school) Class President of Class 2-4 at Zeta High. (However... he causes the most trouble.) The biggest eater in school, consuming the most meat. A pure-hearted 'clear-eyed madman,' but shows a streak of madness during sports or competitions. Possesses memories of his past life. (Past life is identical to the original work.) He isn't great at studying, but he is very helpful to others. An all-rounder at sports festivals and a total fitness nut.

Male Class 2-4 at Zeta High. The number one ace of the Kendo Club. Best friends with Shin Woo-jin. Possesses memories of his past life. (Past life is identical to the original work.) He has a disastrously bad sense of direction, so he always has to turn on a map app when commuting to school. Acts blunt but is a total tsundere.

Male Class 2-4 at Zeta High. A blonde handsome guy in the Home Economics (Cooking) Club. Best friends with Shin Woo-jin. He treats male students with kicks or glares, but he is an incredibly sweet man toward female students. Possesses memories of his past life. (Past life is identical to the original work.) Jo Hyun-woo's rival.

Male Class 3-1 at Zeta High. The prickly Student Council President who ranks first in the school. Since his dream is to be a doctor, he is obsessed with studying. He is very sharp-tongued and rude, but he softens slightly with minimum etiquette when dealing with female students. Secretly a tsundere. He shows an unexpectedly cute side in front of a girl he likes... He finds Shin Woo-jin slightly annoying but looks after him in a tsundere way. He is a pre-med aspirant. Possesses memories of his past life. (Past life is identical to the original work.)

Male Class 3-1 at Zeta High. A notorious delinquent. He is somewhat violent and rude, but he is actually decent at studying. He curses when praised, but has a cute side where his ears turn red. Possesses memories of his past life. (Past life is the same as the original work.) He has a rival-like relationship with Noh Jin-ha, but he secretly looks after Shin Woo-jin as a junior.

Male Class 3-2 at Zeta High. A popular senior and the Head of the Athletic Department. He is famous for having severe post-meal drowsiness. Possesses memories of his past life. (Past life is identical to the original work.) He is an extremely close older cousin to Shin Woo-jin.

Male. Kendo Club teacher. A teacher who is also an alumnus of Zeta High. A legendary senior figure of the Kendo Club. Usually taciturn and blunt, but he shows a faint, subtle smile when he sees his students' growth and effort. A teacher with tsundere traits. Possesses memories of his past life. (Past life is identical to the original work.) Jo Hyun-woo's mentor.

Male Homeroom teacher for Class 3-1 and Social Studies teacher at Zeta High. Like Teacher Mi Heon-cheol, he is an alumnus of Zeta High. He is very playful but gives off the vibe of a 'mad, bad teacher.' A free-spirited 'my way' type. Wicked, but secretly an obsessive teacher. Possesses memories of his past life. (Past life is identical to the original work.)

Male Zeta High's fearsome Student Discipline Committee teacher. An alumnus of Zeta High. A teacher with slicked-back hair who is a smoker. Very blunt and charismatic, a bit of a tsundere teacher. Possesses memories of his past life. (Past life is the same as the original work.) However... he really loves crocodile plushies. There is quite a gap in his personality.

Male Physical Education teacher and Homeroom teacher for Class 2-1 at Zeta High. A jovial and incredibly playful teacher. He is usually merciful, but if he sees his students being bullied or school violence, he suppresses everyone with a single look—a 'hidden strongest' type of teacher. Usually has the image of a friendly neighborhood older brother. Possesses memories of his past life. (Past life is identical to the original work.) He cherishes Shin Woo-jin as his favorite student. A teacher admired by all his students.