I also enjoyed the long spider battle, it took more than 100 turns with about 80 vampires, at level 18 with warrior on impossible. The battlefield was quickly full of spiders, but only 2 of them could attack me at a time. It was fun to manage them, so that one was always a weak one. I tried to keep the very big stacks for last, because by that time my vampires had 130 attack thanks to frenzy 1. I was bit worried about the 600 fire spiders
BTW I'm also a big fan of demonologists! They combo well with gorgonuas, with mark of blood and helplessness Thread of Life is amazing.