M'Hael & Shurenai are correct. Backstab occurs when an enemy is unaware or searching, staggered/parry have separate multipliers to that, but this isn't obvious, so it makes sense folks would think there's a separate back or head hitbox. The only hitbox to be concerned with is where you weapon hits during each animation as damage can be greatly reduced if hitting multiple targets at once as the damage divides amongst them. For example, if doing a wide sweep and you clip a tree/rock/shrub you're gonna be doing half to the enemy and wasting stamina and durability and with crowds of enemies, unless they're weak your less likely to hit for enough damage at once to get a stagger. This is a big reason why pickaxes suck for combat as the arc hits the ground unless you're on top of an enemy, so the ground takes half the possible damage. Final tidbit: Do aim for the head/chest on Wraiths as their hitbox ends before the bottom of their model.