Sorry but I think you have to find a better group. I played through the shadow caves many times without elixirs, and in fact, my first few runs I assumed it was a true elite campaign and didn't even use potions because I assumed they weren't available. That witch is a wrecking ball, and I have been with groups that wipe at her, but I've also been in groups that took her down on the first try without elixir.
Bookmarks