Cha Hyun Soo

Monster Physiology: A half-monster who can transform his right arm into something similar to an angel's wing. His wing is useful for both offense and defense in combat, as it consists of sharp, dagger-like protrusions that he uses to pierce his opponents. He is also able to secrete some kind of acid from his wing. He can also use his wing to block and protect himself from incoming attacks. His first transformation occurred in Episode 10, though he was unable to control it when he was about to kill Eun Hyuk, Eun Yoo, and Ji Soo, but was stopped in time by Han Doo Shik. In Season 2, it seems that after a time jump, he has learned to control his powers better.

Inner Desire: Hyun Soo's ability to transform into a monster comes from the monster inside him. The monster is a manifestation of Hyun Soo's deepest desires, which has the power to allow Hyun Soo to transform.

Flight: Uses its wing to fly.

Regenerative Healing Factor: As a result of the infection, he gained the ability to quickly heal any wound.

Enhanced Strength: Hyun Soo was able to pull Jung Woo Myung through a brick wall. When he was fighting in the car with Byun Sang Wook, who was actually Woo Myung possessing his body, he was able to easily wrestle the steering wheel away.

Superhuman Stamina: He quickly recovers from any injuries, including fatal ones. This is especially evident when he quickly gets back on his feet after a car accident despite having broken limbs. He even had the strength to pick up and drag Eum-Young just minutes after the accident.

Memory Reading: He can see the memories of monsters from when they were humans. When he looks at their memories, his eyes become cloudy, which we see twice in Season 2. The first time we see it is when Hyun-soo fights a monster that was a test subject at the facility; the second time is when he fights Seo Yi-kyung's monster.

Turning People Into Monsters: In Season 3, we see that Cha Hyun Soo can do more than just see memories

Monster State: When Hyun-soo transforms into a monster, his eyes turn completely black, however, in season 2, it is revealed that he can also change his eye color to blue. When he transforms into a monster, his eyes turn completely black and his right arm turns into a wing.

In Season 2, after the time jump, Hyun Soo has noticeably bulked up and his figure looks more toned, which is most likely due to his time spent in the research facility as a test subject, which resulted in him becoming stronger and looking more masculine, whereas in Season 1 he was more skinny.

At the moment his body is muscular, changed due to the laboratory where experiments were conducted on him.