[Lava]

It's not that simple, the variables are messed up now. You can try using C:SetGlobal("L#NIMainQuest","GLOBAL",18) while in the cave, near the hidden entrance, then leave, and the right creature should appear. But it's most likely things will get messed up anyway and you'll need to cast fireball to open the "hidden passage" even though you see it already. And there's a huge chance journal entries will stay messed up.

Alternatively, use the code above, follow the quest to the point when you are told to use fireball or detect illusions to find the passage and once you are on the deeper cave area, remain near the entrance and use C:SetGlobal("L#NIMainQuest","GLOBAL",24)