Ellias Aubec wrote:
Also a CR7 for a group of level 8s is super easy. It should be an easy encounter for 4-6 level 8s.
Sure, but he's got 8 players at level 4.
As for the problem at hand, other than adding more monsters (which, admittedly, is a little boring), or having the monsters fight smarter (which can be difficult), all I can suggest is add a complication to the battle, like tremors or falling debris or the like that gives a negative to hit. Giving the monster an extra special ability/attack could work, too. As in, maybe it's a mutant/special variety of whatever. (Think back to Clara-247 from part 1, and her Precise Shot ability.)