Stamina Sacrifice:
Stamina Sacrifice is a last ditch effort ability that all characters and monster have. However this ability can only be used when they under 100 HP in the case of a monster and under a quarter of their HP in the case of a character.
This ability takes into account that you have been damaged to the point that you are fighting completely on will at this point causing you to put all your effort into a final attack leaving only enough stamina (around 100 SP) to stay standing after the attack.
For low level characters and monsters such as wolves every 50 SP = 10 extra HP damage. For higher levels every 100 SP = 10 extra HP damage.