In Dark Souls, which area is home to the boss Chaos Witch Quelaag?

In Dark Souls, Blighttown is home to the boss Chaos Witch Quelaag.

Blighttown is a vertical, poisonous settlement beneath the Depths. Its wooden platforms, ladders, toxic dart snipers, mosquitoes, and swamp make navigation one of the game’s most memorable early challenges. The area can be entered through the Depths or reached more directly using the Valley of Drakes route.

Quelaag waits beyond the swamp in a domain built around the remnants of the lost city of Izalith. She is a spider-bodied demon with a human upper body and uses fire-based attacks, including sweeping lava sprays. Defeating her grants access to the second Bell of Awakening.

Blighttown is sometimes confused with the Demon Ruins and Lost Izalith, which are later locations connected to the same demonic history. Quelaag’s Domain sits beside Blighttown, but the boss encounter is conventionally identified with that area’s route and swamp.