Master,What are you doing here...?Those are Combine soldier uniforms.So you're traitors?Isn't it obvious?I mean, it sounded fun.It comes with three meals a day, so...• Combine soldiers
Earthlings who have joined the Moon-dwellers' side.Becoming a Combine soldier guarantees safety for you and your family, as well as food and other benefits, but that doesn't seem like it would matter much to the denizens of Gensoukyou.*Gappoi*
A meme in the Japanese Half-Life community, where the Combine soldiers' "Outbreak" line is misheard as "gappoi", the act of grabbing someone's crotch from behind as a prank.