The Fair Lady Quelaan is one of the seven Daughters of Chaos. She is a half-spider half-woman turned demon, changed through the Bed of Chaos, and has absorbed a sickness called 'blightpuss', which lead to her albino complexion. She is rather more docile than her sister Quelaag and is both the leader of the Chaos Servant Covenant and the fire keeper of the bonfire that she sits beside, underneath the second bell tower in Quelaag's Domain.

The Bed of Chaos, mother of demons, was a result of the Witch of Izalith's attempt at remaking the First Flame. She and some of her Daughters of Chaos were devoured, while the rest of the Witch's followers grew mutated demon forms.

Quelaag is a daughter of the Witch of Izalith and, along with most of her family, failed to escape from the chaotic flame and was corrupted by it. Due to exposure to the flame, Quelaag and her sister mutated into spider-like creatures with their upper body being fused to the monsters' backs. She is the Fair Lady's older sister. When their mother, the Witch of Izalith along with their other two sisters became the Bed of Chaos, she fled with her sister. Although their sanity is intact, their lower bodies became bound with demon spiders. When her sister became weakened and blind, Quelaag remained in Blighttown to protect her from anyone or anything that would try to harm her.