This sourcebook for Spire contains:

• Rules for the Blood-Witch, a terrifying character class that deals in deceit, immortality and exsanguination thanks to a mystical blood disease they willingly contract in the depths of the underspire
• The Demonologist extra advance, allowing any character to dabble in powers far beyond their ken and mar their eternal soul in the process
• A list of demons: extra-dimensional horrors bound into unstable equipment by people who really should know better
• The Grangou extra advance: a hedge-witch who deals in community, fortitude, magical curry goat and a cauldron that brings people back from the dead
• The Deep Apiarist extra advance: one of a sect of protectors of Spire who take pilgrimages into the Heart and fight the nightmares they encounter there, replacing their organs with waxen simulacra and filling their bodies with sacred bees
• A list of occult fallout results that GMs can inflict on players that delve too deeply into the dark arts, including: horns, your lies appearing as tattoos on your skin, the worst luck in the universe, and – every night, as you sleep – retching up a grey-skinned, needle-toothed child that bears your face and runs around desecrating altars