In a typical game, a NPC does not play for either side, they do not win at the end with villagers or wolves - they are just that a non-player character. As such they cannot be lynched and they cannot die. They are not playing to full capacity which is why I am not fully sure why veteran players are lynching an NPC. It is a wasted vote unless Cyndia has no idea what an NPC is. They have a roll in the game - which varies game to game but usually does not benefit one side more than another, it is balanced out. It is a way to allow some mechanisms to occur in a game without assigning them to playing rolls and also allow someone to play who cannot play at full capacity.
