Breen knows Gman?

[MTG_Maro]

I wouldn't be surprised if he was somehow altering his appearence to people who see him, but heres a contradictory example: Gman appears as a rebel to the rebels, he appears as a combine to the combine, combine see him talking to a rebel. They would shoot him. Unless he changes his appearence to a universal view but Gordon's. Or he couldn't be changing at all.

 

[Ridge]

See, I'm thinking that the Gman, as we know him, could possibly be just a 'host body' for a Combine ambassador. Or any other species, really.
Taking an important government agent as a body would give him access to BM.

That is what I figured. He is a fairly average (if not creepy looking) person, but seems as though english is not exactly the language he is most comfortable with.

More than likely he is some alien lifeform who assumed the identity of a high-ranking official who was able to get clearance to Black Mesa...