Origin predates computer RPG's. It's from tabletop role playing games, and stands for "non player characters". NPCs are the characters that the Dungeon Master

Origin predates computer RPG's. It's from tabletop role playing games, and stands for "non player characters". NPCs are the characters that the Dungeon Master (DM) creates to guide and influence the story, but the player characters (PCs) are the focus of the story. It's collaborative storytelling about the PCs adventure. An NPC is, by definition, not the hero.