Bawylie
A very OK person
Fiat treshold is that line in the gms mind of "helpless enough" to qualify for tossing the normal damage system and moving to the checkmate or plan-b or whatever.
Its when you cut from orc on guard duty to that same orc having insufficient defenses.
I mean, if we assume the hidden archer vs orc guard is possibly at play for checkmate, then some degree of bored was mentioned. I would think some degree of armored would apply too, since armor is designed to cover vital spots.
But at some point a gm decides against using the system rules for attacker unseen against surprise first round of combat and going checkmate - based on a culmination of stuff in his head. Does guard in full plate vs guard naked play a role other than AC here? If its a cresture with natural armor does a dart throw still have the same pop-n-kill threshold as a longbow?
Etc etc etc.
I see. So if we cast sleep on the orc, we’d all be in agreement that orc would be uniquely vulnerable. But there’s a gray area between that definite candidate for checkmate and an orc who is not a candidate for checkmate that you’re calling fiat.
I suppose the defining line for me would be whether or not a defense against the attack were reasonably possible/effective. Natural armor might be the type of thing that’s nearly always effective, but even Smaug had a weak spot, so that’s a consideration.
I’m reminded of a castle murder box. Where they trap invaders in, dump oil from above, and light the room on fire. There’s no real effective defense except not being in that kill box. It might not be an instant win, but after a bit of time, it’s a certain one.