Idea: When the Source Nightmare in the Black Cove is drawing water from the sea, that should heal it somewhat, making the fight harder. It does hit really hard if you let it, which I appreciate, but at 4 on 1 it dies fast. I actually let it live a couple more turns that I didn't need to to see what it would do.
Good idea with the summoned spiders, but there was only one at a time, and my mage could three shot one of them by poking them with his 20-30ish fire damage staff.