Azurewraith
Explorer
Imagine it is not a tree but an archer. If it blocks my view and I can see a shadow where the archer is then I can hit it with missile fire at no penalty (or maybe at light concealment penalty).
If there is an foe on the other side of the area of darkness, with no objects in the darkness between us, do I have any penalty to shoot them? In other words, is it advantageous for me to cast darkness halfway between my character and a foe, if the foe is out of range of darkness?
PC.....DARKNESS.....Foe
As an aside, I played another game where the darkness spell had no effect on those outside the area of effect. To those outside, the darkness could not be seen at all and had no effect on seeing into or past the area affected. In fact, those outside had no way of knowing darkness had even been cast. In that game, casting darkness on enemy archers was an extremely effective tactic.
Wait unless you where inside the darkness it didn't exist? or rather you had no way of knowing it was there untill you stumbled in and "hey who turned out the lights?"
As for the archer scenario i find it unlikely you would hit as well a square on the grid is a 5ft square which is pretty dam large if you have a human sized target in there, which more than likely wont be standing stock still. I mean go outside get a buddy mark out a 5ft square close your eyes and get them to close there eyes and try lob a rock at them see how many times you score a hit(ok dont do that nothing sours a friendship more than blinding a buddy with a rock)