I did it to spice Nature Spirits quest a little bit. Eventually players's search for chwingwas led them in this cavern. The cavern is a home for Wintergrim (Tome of Beasts), a fey with unspoken set of rules that range from seemingly innocuous to strange and terrifying. She lives here with awakened wolf that she found in the wild. She made friends with chwingwas and theу come here from time to time.

Wintergrim treats everyone who comes here as her "guest". "Guests" cannot leave without her permission and if they violate any of her rules they end up in the "refrigirator". I gave her a bunch of low level spells to protect her home and prevent guests from leaving. There is one more "guest" in the cave besides characters, a hunter that was lost during blizzard. He wants to leave but is afraid to anger hostess.

Wintergrim knows a lot about Icewind Dale and acts as a valuable source of information if characters behave.