Breen is a very human and feeling but still emotionally cold individual. He tricks and manipulates people with no guilt, but in a way that makes him seem sympathetic and kind. He is used mostly as the Combine's puppet during their takeover, but in Black Mesa he had a buisnesslike and strained relationship with the science team. He is also gay and homophobic, and has autism and OCD. He is a shell of his former self trying so hard to pretend he is real still. 