Nezumi

Nezumi translated as Rat in English is one of two main protagonists (the other being Shion) in the novels, manga, and anime franchise No.6. He's a descendant of a race that used to reside in the Mao Forest. During the start it's revealed he is a wanted fugitive who managed to escape a correctional facility. He firsts meets Shion when he snuck into his house to hide from authorities. When Shion finds him he willingly heals and feeds him. Four years after their first meeting, Nezumi's robotic rats give him insight that Shion is being sent to a correctional facility. He manages to find the police car Shion was being held in. He then rescues him and takes him to the "West Block" located outside of No.6. He allows Shion to stay with him. Nezumi saves Shion again, but this time it's from an infection caused by parasites. Nezumi then learns Shion desires to save the city from the disease. He then proceeds to tell him he would view him as an enemy if he goes through with it.