To beat her Before she goes to her lair I had my fighter, laezel, shadowheart and gale.
I put shadowheart and gale in invi used them to turn off the fireplace and walked right in. From the bottom of the stairs I cast create water and kept the stairswell frozen. I had my battlemaster fighter keep her pinned down by frightening her and pushing her around. By the time the redcap reached us she had less than 15hp left. She tried to run away teleporting to the fireplace but slipped on the ice trying to reach the lair. Finished her off right there. The most difficult part was dealing with the redcaps after so I cleared the ice and fold back my characters together in front of the lair access. They have incredibly long jump so beware of that
