Yeah, that's the optimal way to do it. If you don't have a unit with a huge HP pool and some form of MR, high HP is more important than MR. I was lucky enough to have Immortal Karma to clear it. That massive HP pool that allowed her to withstand two full rounds of hits plus her maxed skill gave me plenty of time to kill them.
Sometimes I wonder where would I be nowadays (gamewise) if not for my cute vampire princess.