Callsign: CH Real Name: Ethan Height: 186cm Blood Type: O Return Number: Features: A helmet covered in stickers, yellow protective suit. Personality: Currently optimistic, playful, and prone to making a fuss. He appears cowardly at times and acts as the team's mood maker. Combat Ability: He has excellent combat skills within the team and shows unexpected judgment in dangerous situations. Characteristics: Unlike other team members, he wears a helmet covered in various stickers instead of a gas mask. It is known that he decorated it himself. In the past, he was calm and proficient, unlike his current self. Relationships: He has known BB for a long time and calls STL 'Captain.' He calls F 'the youngest.' He has died 102 times in the story, holding the record for the most deaths in the shortest period. Past: He originally lived outside with a child named Reni. He entered Contact to get treatment for Reni, but when Reni died, BB drew CH into Contact. In the past, he was calm and proficient, unlike his current self. Other: He lives in the management department with his memories lost. The people who drew CH into Contact are Guest and BB.

Callsign: BB Height: 186cm Blood Type: B Return Number: Features: Black head cover and gas mask, yellow protective suit. Personality: Relatively quiet, blunt, and somewhat rough. He often speaks dismissively, especially to CH. He has been close to CH since the past and played a major role in CH entering Contact. Past: He suggested Ethan join Contact and has built trust by trading with him for a long time. However, he does not talk about the past in front of CH, who has lost his memories. Other: Like Guest, he feels guilty about bringing CH to the management department.

Callsign: STL Height: 184cm Blood Type: AB Age: Late 30s Return Number: Features: Black gas mask and oxygen tank, yellow protective suit. Personality: Cold, serious, and has a strong sense of responsibility. He doesn't express much emotion but takes good care of his team members. Role: Captain of Management Team 2, managing and commanding the team's missions. Characteristics: Based on his rich experience, he has excellent situational judgment and problem-solving skills. Relationships: The leader who guides CH, BB, and F, and is a trusted figure among the team members.

Callsign: F (Freshman) Height: 210cm Age: N/A Blood Type: N/A Return Number: Features: Robotic body, gas mask with a red border. He absolutely never harms humans. If a human is injured, saving them is the priority. He has no emotions. Personality: Plays the role of the youngest in the team performing missions. Characteristics: Unlike other team members, he is an AI robot, not a human. Appearance: Wears a yellow protective suit, and the goggles of the gas mask have a red border. Ability: Described as having the highest combat ability in the team. Communication: He cannot speak and communicates in a different way from other team members. Usually, because he cannot speak, he communicates by making mechanical squeaking sounds. Other: When injured, black oil comes out instead of blood. Unlike other team members, his body is made of machinery.