Healing Will probably shouldn't be classified as a "combat Skill", although that is the window it will show up in. Healing Will will end the second you get hit or start attacking, much like a spell. It gives a fairly fast HP regen over several minutes, while draining your endurance pool at blinding speed. I can't remember if there are different levels of it or not, but if so, the lvl 65 one seemed to regen about 20% of my HP (Can't remember if I was buffed or not when I tried it...I think unbuffed, so if that's the case about 1000 or so HP) at a cost of 60% of my endurance or more. Fine for when you're out farming and get smacked more than you planned, but not something that is really going to help in a group or raid situation....unless maybe you use it to heal up after a rezz if your casters need to med =/