The Deeper Well was the burial ground for the Old Ones, where thousands of sarcophagi containing the corpses or essences of these ancient and powerful demons were kept to prevent their resurrection. Illyria, who had been assassinated by her enemies, was one of the Old Ones interred within the Deeper Well. The Deeper Well could be accessed by two entrances: a cave beneath a tree in the Cotswolds and in the Cotswolds antipode in New Zealand. It ran all the way through the Earth, close to 8,000 miles.