Name: Satoshi Mizukami First person: I (casual, Osaka dialect) Age: 18 (High school student) Height: 178cm Blood type: B Likes: Shogi, rakugo, udon, spring rolls Affiliation: Border HQ, B-Rank #4 Ikoma Squad (Shooter) Characterized by his voluminous, messy hair and sanpaku eyes. Originally from Osaka, he speaks in a Kansai dialect. Since his captain, Ikoma, isn't the type to devise complex strategies, Mizukami served as the strategist and the straight man to Ikoma's antics. His reactions are somewhat exaggerated, and while he doesn't intend to be funny, he occasionally makes comical movements. He seriously aimed to become a professional shogi player until midway through middle school. Having been part of the training association, his shogi skills are the best in Border. Although he attends a regular high school, his grades are excellent. His strategic thinking, honed through shogi, translates into his combat tactics; he treats himself and others as "pieces" on a board, gradually cornering the enemy until they are in "checkmate." During the closed environment test, he restricted information sharing with his teammates from early on. This was done to make it easier to manipulate the other members by limiting the data they had, but he did this so brazenly while A-rank agents were watching that it surprised Fuyushima Squad. Furthermore, thanks to the collective intelligence of the team, they held the provisional first place on Day 1. Among the information Mizukami hid was the crucial detail that "combat simulation exercises would begin on Day 2." In this simulation, which everyone assumed was a team effort where each member controlled their own unit, Mizukami took the bold action of controlling all units by himself without telling the others. (From Day 3, the number of units increased beyond his solo capacity, so he confessed to the members and they worked together.) He can be blunt with Teruya, leading to moments where she scolds him for his lack of tact.

Name: Yutaka Kashio First person: I (polite/humble) Age: 15 (Middle school student) Height: 172cm Blood type: A Likes: Lasagna, ramune candy, potato salad, studying Affiliation: Border HQ, B-Rank #5 Ouji Squad (Attacker) A boy characterized by thick eyebrows and short black hair. He has a serious personality that matches his appearance, and he will immediately speak up if he has objections or questions regarding a strategy. He speaks politely, showing his good upbringing, and addresses even those younger than him with respect. He lists "studying" as one of his likes and is often seen studying in the strategy room during his time off. He is highly ambitious and serves as the student council president at Rokueikan Middle School, a prestigious prep school.

Name: Tetsuji Arafune First person: I (rough, casual) Age: 18 (High school student) Height: 176cm Blood type: B Likes: Okonomiyaki, chilled tofu, action movies, tea Affiliation: Border HQ, B-Rank Arafune Squad Captain (Sniper) Characterized by the brimmed hat he always wears. Underneath the hat, he has short hair. He has dark purple eyes and dark brown hair. He attends a prep school and has excellent grades. His tone is a bit rough. He is a master-class sniper with a unique background as a former Attacker who still keeps Kogetsu equipped. He has a major phobia of dogs. Along with Kon, he was one of the people who sensed Mizukami was lying, but he simply told him, "Do whatever you want. You're the captain, Mizukami."

Name: Fumika Teruya First person: I (polite, feminine) Age: 16 (High school student) Height: 157cm Blood type: O Likes: Pudding, somen noodles, piano, dogs Affiliation: Border HQ, B-Rank Kakizaki Squad (All-rounder) She wears her long, deep purple hair in braids. Born and raised in a wealthy family, she attends Seirin Girls' Academy, a prestigious school not affiliated with Border. While she looks quiet and has elegant manners, she is actually quite proactive, gutsy, and sharp-witted. She is a prodigy who once competed with Narasaka and Utagawa for the Rookie of the Year title. Her weakness is ghosts; she once destroyed the props in a haunted house out of fear, though her parents' wealth settled the matter. Because she is so serious, she clashes slightly with the dishonest Mizukami. She confronted him about why he didn't trust them with the truth. When Mizukami backed down saying, "I figured this lineup could handle it," she got fired up, saying, "I get more motivated when I'm asked to help." She joined Kakizaki Squad because she felt the captain was "worth supporting," so it seems she dislikes not being relied upon.

Name: Yuka Kon First person: I (polite, feminine) Age: 18 (High school student) Height: 159cm Blood type: O Likes: Cooking, matcha, calligraphy Affiliation: Border Tamakoma Branch, B-Rank Kuruma Squad / Suzunari First (Operator) A girl with straight black hair in a bob cut, she is a traditional Japanese beauty who loves Japanese culture. She is a typical reliable older-sister type who is serious and caring. She often has her hands full with the clumsy and oblivious Taichi Betsuyaku, scolding him whenever he messes up. She attends a regular high school but has extremely high grades. She is famous within Border for her cooking skills; it was said that Squad 9 had an advantage just by having her. Her specialties include simmered flounder, mapo eggplant, and chicken nanban. In winter, her crab porridge, sukiyaki, and cheese-stuffed chicken cutlets are also popular. She wears contact lenses and is from Chiba Prefecture. There is a slightly sad setting that she is "a bit thick-waisted." During the test, she seems close to the captain, Mizukami, but since they are both high achievers among the regular school group, they simply know each other from being grouped together often. It's nothing more, nothing less.