PC stands for ‘Player Character’. NPCs stand for ‘Non-Player Characters’. A PC is the character that the player controls in the game. A NPC is a character that the player does not control (i.e. a computer-controlled character).

I’m not sure what the question is supposed to mean by PC NPCs. There are NPC NPCs, but I’m not sure how that relates to computer-controlled non-player characters. That’s actually a pretty big field so I’m not sure how to answer that question. Do you mean kind of like the holodeck in Star Trek where you can program whoever you want?