[quote=ERode]
Willpower comes from the fact that, considering END (I assume END is related to stamina) is only relatively decent, medieval druglord dude is gonna need quite a lot of willpower to make it through his travels.And hey, willpower is a necessary component for surviving bad things, right? I think so? And Appraisal...pshaw, who needs that, when you have supa-negotiation~?
[/quote]

Endurance is meant for physical ailments (poison, disease, cold, etc). 

Willpower is meant for mental ailments (fear, and other shit like that. Right now, mainly fear, but trust me, it is the most given ailment. Not too many people with mental ailment causing abilities. Well... give it time and we will get to some monsters that can do shit like that).