Edit: difficulty - medium

I took quest to search Ancestor's ring. At the start 2 corridors contained 2 ghouls with other enemies, and barely made through it. Then I managed to clean 92% of all rooms, until plague doc died in the last room before taking this screenshot. "Okay, I may manage to empty that last room, there cannot be that horrible enemies, because worst were at the beginning." Then I met the collector. Lol nope, abandon quest. Truck you, game.