Like most other characters in the series, Mono rarely speaks. Instead, his personality is shown in his actions, and it was stated in an interview that Mono is naturally protective. Mono appears to be a noble, confident, well-meaning boy who is willing to go out of his way to help others, as shown when he persists on freeing Six from her apparent imprisonment in
the Hunter's cabin and offers his hand to her. He stays by her side, offering his help again when she asks for it despite her initial rejection of his assistance. He has a degree of compassion, being very clearly disturbed by the decaying bodies in the Hunter's house, as well as initially being shocked upon seeing Six in her monster form when he finds her in the Signal Tower.
Although Mono shows compassion for some, he is not hesitant to kill any foes who intend to harm him and
Six. Should they encounter them, Mono is willing to go to any lengths to end them if given the chance, such as being willing to pull the trigger of a gun to kill the Hunter, pulling the lever of the crematory machine to burn
the Doctor, activating electricity near pools of water to electrocute Viewers to death etc., showing that Mono is willing to go to any lengths necessary to survive in the world without feeling remorseful for any resident he does not know. Mono is also notably cautious of his surroundings, and resourceful enough to use various objects in his surroundings to evaluate the integrity and safety of the path forward. His official description indicates that the character is quite purposeful and stubborn in achieving his goals.
Mono's main feature is that he likes to wear various objects on his head that hide his face, which may indicate his shyness or unwillingness to show his personality.
[3] His description also claims that his paper bag helps him forget that "the world hates him and wants him to fail", which may mean he considers life to be cruel against him.
In the climax of the game, Mono is injured and attempts to walk a straight path to the Black Tower only to be confronted by
the Thin Man once again. Mono, who has grown tired of this world's apparent resentment towards him, removes his headwear and ultimately chooses to fight the Thin Man head on, and with his powers, he succeeds. This shows how tired Mono has become from hiding himself from the cruel nature of the world.
After his encounter with the Thin Man, Mono has become braver. As when he faces off against monster Six, he fights her directly rather than running away and only fighting when given an opportunity. He is also shown to be more brash as well, as he continuously yells at Six to get her attention and to weaken her, despite how much pain both of them seem to be in. When he finally returns Six to normal by destroying the music box, she and Mono attempt to escape the Signal Tower once it begins to collapse. However, Six leaves Mono for dead and escapes the tower herself. Mono, shocked and saddened over his friend's betrayal, loses the will to keep on going and resigns himself to his fate as he sits on a chair inside the tower.
