The Hero's Path

The cave where Astral resides should be darkened, but I managed to illuminate it almost completely from the adjacent area using scouting and a silent stalker.

Argh! I don't know how to overcome this. It seems you can't prohibit certain perks on the map, nor can you control the fog of war over a specific area. Luckily, this is a useless perk from a skill that is practically useless on this map – very few will take it.
The creature mishmash is a storage place for all sorts of purely technical things. Unfortunately, it's impossible to get there. The portal is there solely to remove the editor's warning that "there must be at least 2 two-way portals on the map."