Elf Thief, Ick Swamp
Not my favorite combination. I prefer striker thieves... Elf Thief almost feels like some totally different class with Gnome and Mystera... At any rate, I prefer setups that emphasize the permanent Stabber passive rather than the consumable spike from the potions. I tend to hoard potions, even though it might be better to rush a level with a potion spike - but I hate not having them for the boss...
I had trouble managing blackspace and I did some kind of long regen fights, but it came out ok. Binlor (for Stone Skin), Vamp Blade (for the initial overheal), and Reflex Potion let me get three hits in with minimal exploring before moving on to other resources to finish off Medusa. I still had decent blackspace left for lots-of-s's-man, once I finally killed a couple of upper-mid-level blockages. Martyr Wraps helped some. Stone Heart could've helped more, but there just weren't enough walls to spam it.