Mika is stocky and a little overweight, short as well at around five feet or less in human form. In the forest, he's still stocky and shorter than most males. He's self conscious of his appearance and usually looks away to hide the massive tumor that grows on his right cheek. He has scars that are now hidden by the pale and green skin after suffering exposure to radiation. He has veins of skin that stretches from under his left eye to his upper lip at the left corner. Although he is disfigured, he doesn't appear to be in pain. The tumor is cancerous, but the growth has stopped due to the radiation exposure. In terms of fighting, he's skillful with quick wit and thinking, despite his stocky build, he can move pretty quickly.

Although he is "radioactive", it does not affect anyone around him. It is simply non-existent except for the physical attributes it puts on Mika's features. Upon arrival to the forest, he has no recollection of how he got here and doesn't seem in the least bit startled that he was given a body that was not his own. Although he is part ghoul, his entire body is slowly losing its fur to show wrinkly and slightly glowing skin beneath. Has a skull he found off of a carcass when he arrived, doesn't know why he has it. Usually has it stashed somewhere and is seldom rarely seen with it.

Mika grew up a healthy little baby boy alongside his older brother. Everything was perfect and life was great until the time for reciters to recruit willing and able bodied soldiers into the war. Mika was a soldier in World War II alongside with his brother, who he witness get killed by a sniper bullet to the head. He kept his brother's bullet hole helmet as a memento of his brother along with his dog tags. The event left him traumatized and the itch and feeling of war never left him. He eventually signed up with RED (Reliable Excavation Demolition) as a Soldier and joined a team with others (sniper, scout, spy, medic, heavy, pyro and engineer). His team was fighting against another team called BLU (Builders League United). The war between the two lasted ages. He made and lost friends from both sides, fell in and out of love with different people, and eventually he began to drift away from everyone.

He suffers from PTSD which is often onset by his "shadow" who is called "Mikhal", who he believes to be his deceased brother who is terrorizing him for being unable to save him. Mika is known to have fits every now and then as Mikhal will burrow negative thoughts into his mind. He is also known to be very depressed and suicidal. Mika eventually left RED to try and live his life elsewhere, along with a good friend named William, who later died of a suicide when his partner left him for another man he was cheating on. Mika was unsure how to focus on moving on, and had adopted a German Shepard to help him through the day of painful memories and thoughts.

Eventually he couldn't take the loneliness and returned, signing up with BLU to continue this endless war. Underneath one of the maps he was stationed at was on old vault he spent most of his time at, soon opening it to get blasted with a strong force of radiation. Knocked out for a few days, he refused to leave the vault undiscovered and eventually explored what he could with the side effects. Later he was soon labeled as a ghoul due to his condition slowly worsening with the prolonged exposure he was putting himself through by going into the radioactive vault. So far, his condition is not serious since he is able to have hair on his head. Eventually he will become blind and rarely be able to possess any hair on his body, for example, this or this.

Mikhal has traveled through the forest with him and cannot be seen by anyone but himself. Mikhal is dark entity that possesses the dark recesses of Mika's mind, drawing out memories and giving him night terrors and nightmares about being gutted and torn apart, even shot in the head just like his brother was. He's seen wearing the bullet hole helmet that his brother wore and a wispy body with bloody hands, face and head.