Post/Author/DateTime	Post
#1 The_Simbul_of_Aglarond Aug 26, 2014 18:00:48	I had hoped the mechanics of these spells would have finally died in the 3E era but it seems like the spectre of hitpoint counting has returned...   Essentially there are only two ways to cast these types of spells:   A) Cast them blindly, hoping the current hitpoints of the target fall within the spell threshold, and potentially wasting a high level spell slot and an action. B) Use out of character knowledge or estimated calculations (i.e. metagame) to decide whether or not to cast the spell upon a target.  This can range from something as complex as memorizing the hitpoints of various monsters to something as simple as noting the class/size/type etc of the adversary and assuming a certain range of hitpoints.  Even the most innocent players will find themselves inadvertently metagaming on future uses of these spells once they successfuly slay an undamaged creature---since thereafter may assume any non-unique/non-advanced versions of that creature they encounter henceforth will be automatically overcome by it.   None of this is helped by the fact that you can only cast Power Word: Stun or Power Word: Kill once per day, thereby giving greater incentive to try to look behind the curtain rather than play in an immersive fashion.  While any spell with a saving throw will involve some degree of possible metagaming, they are nowhere near in comparison---a creature can always roll a 1 on a save they are proficient in or a 20 on a save they are not---but their hitpoint threshold is a capped and a rapidly depleting number with each round.
#2 Lord_Ventnor Aug 26, 2014 19:48:34	I think if I were a DM, what I'd do is allow the player to make an Intelligence (Investigation) or Wisdom (Perception) roll against those foes as a free action. On a success, I'd let them know that they think that the spell would work if the HP threshold was low enough, and that they think it wouldn't work if the HP threshold hadn't been passed. But that's just me.
#3 iserith Aug 26, 2014 20:17:10	Why don't you just say that characters do have a sense of whether or not their spell will be effective based on their experience as adventurers? In other words, just assume a base level of competency for characters that can cast 8th- and 9th-level spells.The players can know the hit point value and that translates to the character's ability to judge how well an opponent will resist their magic.   Or just stop caring about metagaming. It's not the only path to immersion. The metagame is a useful tool to move the game forward.
#4 Kalani Aug 26, 2014 20:59:03	You typically know if a creature is at half hit points or lower. See the sidebar "Describing the effects of damage" (phb 197).   A creature below half health looks a little beaten up (scrapes, bruises, etc). While the game does not use the term bloodied per se, thats effectively what they are describing.   PCs can extrapolate an approximate HP total for the creature the moment it hits bloodied, and can gauge (with a margin of error) the relative damage required for them to cast the spell.
#5 Psikerlord Aug 27, 2014 2:23:47	Mearls in his escapist interview suggests this uncertainty was intentional, to create more suspense.....?