
Cursed Cutlass is a no-brainer now that I think about it, because Crusader is immune to its curses anyway, and the other two characters aren't going to be using resists. What do you mean by other potions? Does the boss have some corrosion or weakening? That won't be good...
By the way, are there any significant subdungeon items I'm still missing? I think someone said I'm missing the most interesting items, but aside from the Scrying Orb, I haven't found anything that affects the game that much.