Know enemy's HP

[Yogibear41]

Other than the combat awareness feat is there any other way to determine exactly how many hit points a particular enemy has?

[Inevitability]

Suppress negative energy resistance/protection. Disable all fast healing and regeneration. Zap them with Inflict Minor Wounds until they die. Note down the amount of expended spells. :smalltongue:

[SilverLeaf167]

If Pathfinder material is allowed, the Slayer Talent called "Blood Reader" gives you the exact HP of any living creature you spend a move/swift action studying, at will. Requires a 2-level dip in the class though.

[NevinPL]

Suppress negative energy resistance/protection. Disable all fast healing and regeneration. Zap them with Inflict Minor Wounds until they die. Note down the amount of expended spells. :smalltongue:
That.

Or homebrew the "Living Anatomy" perk from "Fallout: New Vegas".
Although you'd be taking a Sphere of Annihilation to couple of "walls" if you do that...

[IcarusWulfe]

I believe that the spell deathwatch does exactly this.

[SilverLeaf167]

I believe that the spell deathwatch does exactly this.

Nope (http://www.d20srd.org/srd/spells/deathwatch.htm). It only gives you a general status. The most it tells you about their current HP is whether it's below or above 4.

[Palanan]

Masters of the Wild has Power Sight, a first-level druid spell that tells you a creature’s HD.

It’s 3.0 material, and isn’t that precise, but it at least gives you a ballpark estimate of what you’re facing.

[Jormengand]

Power Word Kill will tell you if it's above 100... :smalltongue:

[BearonVonMu]

In Pathfinder's Path of War, there is a Scarlet Throne maneuver that allows you to use Sense Motive to detect if an enemy is at 20% or less HP. This is because the maneuver requires the enemy to be at 20% or less for the power to function.
It might be possible that Sense Motive could be used in general to get a sense of how wounded a foe is.

[Necroticplague]

Suppress negative energy resistance/protection. Disable all fast healing and regeneration. Zap them with Inflict Minor Wounds until they die. Note down the amount of expended spells. :smalltongue:

If you want to save spell slots for the same effect, you can use needles from the BoVD.

[Inevitability]

If you want to save spell slots for the same effect, you can use needles from the BoVD.

Also a good idea. DR is harder to suppress than negative energy resistance, though.