Not sure she's ever given me 4. That might be the problem. I may need to finish something else to unlock it. I did finally finish the Warlord Silver. Now I have every Silver done except Assassin (need to unlock Goblins first, I think) and Priest/Monk/Paladin, the latter two still need unlocking. I've been mostly focusing on Unlikely Hero unlocks because they're fun. :p
Hm, no. I've bought my L2 Witch Hut, and not only have I unlocked Rock Garden, I'm pretty sure I've completed quests there. Maybe I completed 4 and don't remember, but if so I don't have 5. I don't have 4, it's not on my quest list.
If your apothecary is selling strength potions, you beat 4. 5 is in berserker camp, unlocked after beating Creeplight Ruins. It is a Warmonger Sorcerer.
We made an expansion and it is awesome. Really, you should check it out, especially if you're looking for some extra challenge.
Okay, I can has it unlocked now. I understand why that item would be nearly necessary to finish that challenge. I'm very proud that I got him down to 57 without it though.