From the Journal of Jacob Cayle

I really need to work on my tactics. For instance, throwing up the wall of fire first and then summoning the fire elemental would have been better than reversing that order. Not that it would have made a huge difference (as the invisible mage would have still dispelled the summon) but it would have decreased the effectivity of the archer and also done some initial damage to the trolls as they charged us. While this could be viewed as a minor mistake; especially considering we defeated them and not one of us died; it's mistakes like that at critical junctures that get people killed.

That being said, throwing up walls of flame to divide our enemies and hinder their ranged attacks isn't a bad idea, and it's something I must remember to continue doing in the future (assuming we aren't in a forest of dry timber or something like that).

In other matters, the mage who was helping (and perhaps leading) the trolls in their attack on us was wearing a crystal which tends to show alignment with (or at least control by) "the enemy from the deep" (or whatever we're calling it). The fact that we ran across one of these scoundrels is a disturbing sign indeed. Either there are enough of them in this area that we can happen to just stumble on them (which means there are a lot of them around) or they're following us. Either option does not bode well. The latter has obvious implications. The former means they are likely after the same thing we are (or already have it). And it's quite possible that all of the above is true. We must be on guard, even more so than normal.