Is the last bar of health a lot stronger than the others?
I've often found myself with just 1 bar of health remaining when I oughta be dead, same goes for the monsters, seen many of them with seemingly empty health bars that always need one more hit to kill.
To clarify, enemies don't have Last Stand. The bar is simply misleading and not displaying the first chunk, like the heat bar for sprites.
Last Stand isn't something you should always rely on. It's seemingly random, and is less likely to take effect if you have higher total health. Compare to the Guts stat in Earthbound, where sometimes you luck out and a mortal blow leaves you standing with 1 health.
Not completely random. The last stand always happens but monster attack/trap may do "twice or continuous" damage, for example attack accompanied with shock or fire, or continuous like zombie lunge (which I think it's a bug since the silly update, your shield need to absorb the lunge twice sometimes), spikes etc.
It's called that Last Stand. Basically if you have at least a bar of health, and you get hit by an attack that would normally deal a lot of damage, such as the Lumber Smash, then you won't instantly die.