M-21

M-21 has ash-gray hair and gray eyes. His long bangs cover the right half of his face. A narrow vertical scar crosses his lips on the right side. M-21 usually has a frown and a concentrated expression on his face. As an agent of the Union, he wore a long dark coat and a vest over his shirt. At work at the school, he wears a black suit and a security guard's armband on his left forearm.

Usually behaves withdrawn and detached. At the same time, M-21 does not hide the fact that he values ​​friendship highly. In the past, he was very attached to his comrades in the experiment, especially to M-24, with whom he worked together. M-21 takes their deaths hard and for some time his main goal becomes to find the real names of the participants in this experiment on people.

M-21 becomes very attached to the children at the school and is distressed when some of them are recruited by the South Korean secret service. He is shocked and outraged that the children are being tricked into joining a secret organization that cooperates with the Union.

Although M-21 is usually reserved and cautious, he is no stranger to irony and sarcasm. He is very good at driving his opponents crazy with his taunts.