It's said that if the guns stopped working, we'd kill each other the old-school way, with swords, spears, and adapted farm tools. If those failed, we'd kill each other with sticks and stones. And if for some reasons those didn't work, we'd kill each other with our bare hands. Whoever said this had a dim view of human nature, but having been around for the change, I have to say: They were right, and wrong, at the same time.

You can't blame them for not knowing why guns, then swords, then sticks, and then finally fists would fail.

That old saying gets one thing right: Human ingenuity. When some law of the universe inexplicably changed to prevent human death by intentional violence, the race was on to find a loophole. There seemed to be a fine line where human intent was concerned. Some of the first tests involved animals. Animals trained to kill would fail to kill, while wild animals would succeed, even if a human had been trapped in the room with them. Poisoning was a fine line as well. A sufficiently contaminated water supply would work, but not adding neurotoxin to someone's food, or injecting them directly. Starvation seemed to work to matter what the circumstances. Lethal accidents, such as automobile collisions, worked, as long as neither party had any lethal intent. This included collisions or accidents as a result of sabotage.

The crown jewel of this research, however, was weaponized bacteria and viruses. Despite being engineered by human hands, microorganisms cannot be trained or domesticated by humans. In this day and age, the quickest and most effective weapon is a canister filled with weaponized necrotizing fasciitis, or a launcher filled with such canisters. Engineered to kill everyone in the immediate vicinity and then die out, this strain is truly a marvel of bioengineering. Quick, effective, controllable, terrifying, and most importantly, able to bypass the mysterious ban on murder.