@mrfugi3
Ya I gotcha, interesting though that you would know if the enemy is low on hp.
If you've faced an enemy before then you should roughly know its health total. Also, if you're attacking a goblin then you know it always has low hp :P
Additionally, I usually play in games where you can make perception checks to tell roughly how wounded an enemy is, or the DM just flat out tells you when it reaches <half hp.
