6. Gregory House (House M.D.)
FoxEverybody lies! Kings Landing is no exception. If House were to limp into the Red Keep, he would know exactly what kind of people he was getting involved with. Supremely intelligent, House would be able to match wits with everyone from Tywin to Varys and if he wanted the Iron Throne for himself, you can bet he would take it. He laughs in the face of authority, has no patience or sympathy for other people and he's an expert at rooting out people's weaknesses. House would figure out Joffrey's parentage in less than a day and be smart enough to keep it to himself. Don't worry about him warning Cersei and giving her time to escape, House doesn't really believe in the whole people are inherently decent thing. House would be selfish and ruthless enough to look after himself on his way to the top. And having some medical training would definitely come in handy in case of he takes a few dozen arrows from just about everyone.