Near the end of the Buck quest line it occurred to me: Is Buck real?
Think about it. He shows up after nearly every quest in places he shouldn't have known Jason was. He has a big buck tattooed on his chest in a style that reminded me of a spirit guide. He never physically interacts with Jason aside from the knife fight at the end, and the last fight with him seemed like a hallucination. Furthermore, Keith never says anything about Buck, nor ever refers to him. (As far as I know, I haven't finished the game yet.)
His way of taunting Jason and always knowing where he would be next seemed unnatural. And there's also no reason Jason shouldn't/wouldn't have just shot him right before the knife fight.
What do you think of this?
"You said it yourself, Kain - there are only two sides to your coin..." -Raziel http://implicateevolution.com
Keith did make one reference to Buck after the boss fight, asking if Jason was sure he was dead. And I can imagine, after what he's been through, Keith doesn't even want to think about Buck, let alone talk about him.