The Deep Realms, an expansion for Talisman Revised 4th Edition designed by Jon New, connects the Dungeon to the City by introducing the corpse-filled, rat-infested Deep Realms. Players can cross through the Deep Realms by means of a precarious and perilous bridge on one level, or venture even deeper underground, into an ancient system of dark tunnels inhabited by rats and feral pets, wraiths and zombies. In these gloomy places, players will encounter incredible danger, but may also find tantalizing rewards for their bravery.

The Dungeon and The City expansions are required to use this expansion.