Stunning Fist

The knockout strike is a staple of film and television. The swift blow to the face or back of the neck – often performed with a pommel or flat of a sword – that instantly and silently stuns an enemy, allowing the hero to continue sneaking through an enemy complex. It’s hard to accomplish in D&D, doubly so at higher levels when mook expected to only last half a round of combat might have dozens of hit points. Some game systems didn’t even try; I remember eye rolling at my Palladium books during high school where they justified and defended their poor knockout rules with a little rant about how hard it is to accomplish in real life.

3rd Edition D&D tried the hardest to codify knockouts, with a separate pool of health for nonlethal damage. In 4e and 5e the final blow can be a killing or knockout blow, meaning you need to do 100% of a creature’s health in damage to knock them out, replacing the single swift tap to the back of the neck with several violate stabs to the chest and throat preceding the final tap.

I rant, but this is one of those rules that’s practically impossible to functionally design, or at least codify. There needs to be a way to knock out foes to take them alive and replicate the cinematic stun, but it can’t be too easy or the PCs will do it to the boss monster… or a foe will do it to a hero. So there can’t be a hard and fast rule where a single failed Constitution or Fortitude save rendered someone unconscious.