You are my special

Two friends living together, struggling with money, while balancing part-time jobs and university, have been practically forced to let a third roommate in so they can now split the rent with three people. They had little to no knowledge about a person that is coming to live with them for the rest of their school days. They have been told about what kind of person he is, where he lived, and stuff like that. There is just one part of his description that the two friends find very disturbing...