Unfortunately, it seems that the human who uploaded all those ROMs was into action games, so there weren't very many NPCs around. Thus we devised a plan B.
"We managed to round up the worst criminals, and a few NPCs bravely volunteered to be fused with them in an effort to create beings no longer able to fight."
We carefully set the attributes, ran the Chimerization process, and hey, it seemed to work. We had new beings who were both incapable of and uninterested in violence, basically NPCs.
"But it didn't work. Apparently the process was unstable. Spontaneous flip-flops of attributes began occuring, and suddenly we had characters with NPC invulnerability and the ability to attack."