Sheol I is used as a control center for the operations of the Rephaim. They import Scion-captured voyants. Sheol I is completely inaccessible except by train, which arrives and departs once every ten years. The purpose of Sheol I is to train, indoctrinate, and subjugate human clairvoyants. Those who fail their tests are forced to live in squalor in the Rookery, and they are starved and beaten by anyone with higher status. Those who succeed in their tests are made to fight the Emim. The humans' ranking is shown by their jacket color.
Sheol I also serves another purpose. It draws the Emim away from the rest of the population. The Emim are attracted to ethereal activity. After Paige Mahoney stages the revolt during Blood Season XX, the penal colony is destroyed and now the Emim "will be tempted by the great hive of spirits in London."
The clairvoyants in Sheol I live in poverty and are starved and beaten, but they are free to use and develop their abilities. They become slaves and entertainment for the Rephaim and guard the city from the Emim. There are about thirty Rephaim living in Sheol I.
- Residence of Magdalen: Warden's residence
- Residence of the Heir: Kraz's residence
- Residence of Oriel: Terebell's residence
- Residence of the Suzerain: Nashira's residence
- The Rookery: the squatter settlement of the cast-out clairvoyant performers, called harlies
- The Guildhall
- Port Meadow: a training field outside of Sheol I
- The House
- The Room
- The Old Library
- Residence of Balliol: How the colony stays in touch with the Archon in London.
- Ivy Jacob
- Felix Samuel Coombs
- Michael Wren
- Eleanor Hahid
- Carl Dempsey-Brown
- Joseph Biwott
- Julian Amesbury
- Sebastian Pearce
- Liss Rymore
- Amelia: a soothsayer
- Chales: a cryomancer and harlie
- Duckett: a catopromancer and black market smuggler and supplier in Sheol
- Lotte: a seer and harlie
- Tilda: a whisperer and harlie
- Ella: a harlie with an unknown power
- Kathryn: a voyant soldier with an unknown power
- Overseer Beltrame: a medium soldier in charge of the performers
- Cyril: a harlie
- Sheol I is mainly inspired by the heavenly city described in the medieval poem Pearl.