Kōhei Katsuragi

Kōhei Katsuragi is a student and the class representative of class 1-A along with Arisu Sakayanagi.

Appearance
Kōhei is a well built young man of above average height. He is bald due to an illness and has a large body frame compared to other students, which contributes to his intimidating appearance.

Personality
Kōhei is an intelligent student who worked very hard to reach class 1-A and became one of its representatives.

He is a serious man who adheres to the rules of manners and good conduct as he reprimanded another student of the class for making fun of Ken Sudō and his classmates. He was calm in telling Ken not to get easily provoked by his classmates' actions, but his demeanor intimidated him into stopping from arguing any further. From this display, it shows he is one of the few upper students who have no problems in associating with those of the lower classes or that he was simply annoyed by their antics.

He expresses slight anger when some of his failures are mentioned, such as when Kakeru Ryūen brought up his rejection after trying to join the Student Council.

Abilities
Along with Arisu Sakayanagi, Kōhei is one of the leading figures of Class A and even has a faction following dedicated to him.

Academic Abilities
Not much is known about his academic background, but it is presumed that he's one of the class top-rank as being one of its representatives.

Intellectual Abilities
Kōhei won Honami Ichinose's recognition when she reported him to her teacher, Chie Hoshinomiya, as someone to watch, along with notable figures from each class. This suggests Kōhei having enough ability to pose a threat to class 1-B.

Plot
Kōhei was first seen besides Arisu listening to Manabu Horikita as he officially welcomes each first year student into the school.

Kōhei was next seen with Arisu along with several other students being congratulated and was asked the extent of what they know about the S-system.

He is next seen with Arisu looking at the scores of each class, remarking the advancement of class 1-C before following with a statement that Kakeru Ryūen is a dangerous man, to which Arisu simply responded by asking how boring it is and walks off.

During the school cruise, Kōhei was taking a lunch at a fancy restaurant within the ship. He reprimanded his classmate Yahiko Totsuka for inciting Ken Sudō, noting the possibility of bearing the consequence of losing points for bad behavior and to conduct himself a proper A-Class student should. Kōhei advises the D-Class students from keeping out of trouble. He then continues on by asking if Ken intends to repeat his earlier blunder, stopping the commotion from escalating.

After arriving on the deserted island, his class set up their camp inside a cave. He was spotted along with Yahiko conversing in front of the entrance by Kiyotaka Ayanokōji. Then sometime later, Kōhei appeared to confront Suzune Horikita and Kiyotaka, fending them off after knowing their intent to go inside their camp.

It was revealed that Kōhei had made a contract with Kakeru, unaware that he was being deceived in the process. Following that, at the last day of the survival test, Kōhei showed an expression of disbelief after knowing that class 1-A ranked only in third place, clueless that it was because of Kiyotaka's elaborate scheme. After that, Kōhei was assailed with voices of discontent by classmates complaining about their losses. Masayoshi Hashimoto came and commented about the outcome being pathetic.

Seemingly unfazed by the insult, Kōhei accuses him as the one who told Kakeru the name of class 1-A's leader.

Trivia

 * He shared the same student identification number with Haruki Yamauchi.
 * For 2nd year, his ID is changed to the same one as Sō Shibata's.