Mano is a Chachaoong that follows Bi Gak. Bi Gak favors Mano due to the fact that he is a doctor, which is extremely rare among Chachaoongs and because of this, he has special protection from Bi Gak. It seems he has some sort of connection with Sae Ha as he seemed intrigued to learn Sae Ha was residing with Yu-Jin. Sae Ha was previously his teacher.
Mano has black hair with red and green dyed tips on the front. He is always seen wearing a white lab coat with a red arm band on the left arm, and a pair of glasses with one red lense and one green lens. It is implied that the lenses may be 3D glasses. He wears green and black beneath the white coat. Though he smiles often, the smile usually has a cruel or sardonic edge to it.
Mano initially comes across as someone who is amicable and laid back but can easily switch to being threatening toward people he dislikes. He does not particularly seem to care much about the people around him though he does get annoyed at his patients for not taking proper care of themselves. Nevertheless, he does not view it as his responsibility to save lives. He believes that the power of life and death are not in his hands, even as a doctor, as he is not God and has a very casual way of dealing with death.
He comes across as somewhat sinister and deceptive. He also appears to be quite loyal to Bi Gak, but still cares about his teacher, Sae Ha, to the point of calling him Teacher, often. He seems concerned about why his teacher left him, shortly after he killed one of the patients who said he'd rather to die. He also states, before he dies, "I always listened to you."
As he holds a knife to his throat, he shows a different emotion, fright. He claims that he was afraid of a certain "guy" saying that he was terrifying, then taking his own life. Just before his death, he tells his teacher he was happy when working with him.
It's unknown what the full extent of Mano's abilities are. He claims to have a weak body but has been seen materializing small blades like scalpels. As he seems fairly close to Bi Gak, it's likely his abilities are more significant than he lets on.
When threatened by two unnamed Chachaoong, he pulled a syringe from his pocket, but was stopped by Gamun Bi before he was able to use it.
His skills as a doctor is not known, but he shows knowledge of being one, and previously being a student of Sae-Ha, who was also a doctor.