Why it does so much damage? Because the code says something like, "Get the current HP of the target, then deal exactly that much damage to it." So a level 35 brawler who has this skill and Everfrost access can find a way to sneak down in Permafrost where the sub-50 solo ice gaint are and assasssate them one every 5 minutes. Assassins... a class you'd sort of expect to have an ability to outright kill weaker enemies... don't have anything at all like this. Even "Assassinate" can't one shot most exp mobs. I'd even say its something most predators should have, rangers can snipe off mobs with headshots while assassins knife them in the back. SOE didn't think this one through at all, or they put in a really botched implementation of it.