Blighttown -> Quelaag's Domain | Walkthrough Dark Souls Guide
Last update: 06 April 2023
Enter the area through a hole in a white vortex. Inside you'll find two creatures with eggs on their backs. Ignore them, because they are not attacking you.
Fight with Chaos Witch Quelaag.
After the fight, go behind the arena. In the next room use the lever to ring the second bell.
Go down. You'll reach a location with a round platform (this is not working elevator). Hit the side wall in order to reveal a secret passage to the bonfire (and other).
Go through the secret passage. The way is blocked by a creature with eggs on its back. Talk to it and say YES on its questions.
You can now use the bonfire here and talk to Quelaag's Sister, leader of Chaos Servant Covenant.
A further way leads down the stairs to Demon Ruins. But this is a difficult location so it is worth to take a look at other places, like Darkroot Garden for example!