Chaos Witch Quelaag is a character from the video game series Dark Souls. She is a boss encountered in the Demon Ruins area and is known for her spider-like appearance and fiery attacks. Quelaag is the sister of Quelaag's Sister, who is a benevolent character that aids players in the game. Quelaag was once a human but transformed into a chaos witch due to her connection with the Chaos Flame. She wields a powerful sword and uses fire-based magic in combat. Players must defeat her to progress in the game and uncover more of the story surrounding the Chaos and the Fair Lady.