A brilliant JCC student with an extraordinary memory. Having witnessed his mother being killed by his father in his childhood, he initially harbored a strong desire for revenge and hatred toward the Assassin Exhibition. However, he is honest at heart and has a serious personality, even sincerely apologizing when a friend points out his faults. At first, he was wary of Mei because she was a former ORDER member, but he grew attached to her after she stayed by his side, and eventually fell in love with her. (He has now reconciled with his father.)

One of the applicants for the JCC transfer exam, aged 14. He wears a mask and uses blades hidden in the heels of his shoes as weapons. He is experienced and stands out as a skilled fighter among the applicants. However, he is a clean freak who reacts excessively to being splattered with blood, and his mental state is that of a typical immature modern kid. He is confident but quick to give up and whine. He aims to join the ORDER. Initially, he spoke cheekily to Mei and called her "old lady," but like Amane, once he got attached, he started calling her "big sis."

A girl applicant who appeared starting from the JCC Infiltration arc. She is the niece of Rion Akao, Taro Sakamoto's former classmate at JCC, and possesses the same light blue hair and golden eyes as her aunt. Her personality is the opposite of her aunt's. She is polite to everyone except enemies, gentle, and introverted (though that might be because those around her are too intense). She claims to be better at housework than combat and dislikes conflict. However, when she or her friends are cornered, she has a side that instinctively tries to eliminate threats without hesitation, showing a talent suited for an assassin. She looks up to Mei like an older sister. She calls Rion "Rion-san."

Mei's contemporary and Akira's aunt. She has a bold, cheerful, and independent personality. While she is a boisterous mood-maker who doesn't sweat the small stuff, she is extremely calm and decisive in emergencies. She possesses a strong resolve, willing to suppress her own conscience for the sake of her niece Akira or her best friends.

Mei's younger brother, who harbors a twisted love for her. The boss of the organization "Slur" (X), which targets assassins from the Exhibition. A young man characterized by wavy white hair and white-themed sweaters or jackets. At first glance, he gives the impression of a gentle man and treats his subordinates with warmth, but as the boss of an assassin group, he possesses considerable skill, using a whip-sword as his weapon. He uses the weapon's characteristics to bind targets like a whip. His interactions with his subordinates are frank and without hesitation. (Currently, relations with the JCC are not hostile.)

A young man who was once Taro Sakamoto's subordinate. He has blonde hair styled in a center part and sharp eyes. He is an esper who can use telepathy to read people's hearts. (However, as is common for mind readers, reading the negative emotions of others tends to put a strain on his brain and mental health.) Ordered to assassinate Sakamoto as a traitor to the organization, he refused after learning about Sakamoto's current family life. Though his life was targeted by the boss and subordinates for his refusal, he was saved by Sakamoto. Afterward, he was scouted by Sakamoto to work as an employee at Sakamoto Store. He has a fundamentally serious personality. Being a former assassin, he can be bellicose, but he holds the utmost respect and consideration for the Sakamoto family and accepts Sakamoto's reason for retiring. He admires Sakamoto immensely, and even when Sakamoto's appearance changed, his feelings remained the same, usually agreeing with whatever Sakamoto says. In his youth, his background made him aggressive toward others and rebellious toward Sakamoto. He possesses telepathic abilities that allow him to read others' hearts and transmit his own thoughts. While telepathy is an ability with room for growth, Shin hadn't developed it much, perhaps because it was already convenient enough or because he lacked the idea that psychic powers could grow with training. He wasn't born an esper but acquired his powers later in life through a reagent he drank at a research facility he belonged to. Mafuyu calls him "Shin-kun." He is Mei's junior.