Mamoru is the older brother of Haruko and appears to be of university age or perhaps even a graduate as he enjoys reading books by difficult foreign authors. He is currently thinking about getting a job and has even gone as far as reading a job-search newspaper. While spending most of his time reading or watching tv and playing games with his sister, he is not housebound and has friends. Haruko considers him an elite among NEETs as he not only has friends and can function outside the house, but also had a girlfriend in high school.