The Brain Maze is a gloomy plain and constitutes the first test to the Key of the Abyss, referred to as Level of Dominion in the official Interplay walkthrough.
When leaving the gate in the centre, we're attacked by a Wielder, and the plain starts to demerge into various terraces which Adam has to descend in order to find 16 brains and feed them to an automaton. The brains are scattered across the floor but are also hidden inside the various disorienting tunnels that characterise the architecture of this level. Shedding some light on the confusing layout of this place, Derell Licht has kindly provided a hand-drawn Map of the Brain Maze.
After having put all the brains into the designated automaton, a bell will toll announcing the appearance of Vine, a powerful creature who has dominion over this area. Defeating him will level the terraces again and reward us with the Power of Dominion scroll, which will protect Adam from an illusion created by Belial, in which he finds Rebecca chained to a rock on the Island of Threads, prompting him to let down his guard and consequently giving Belial the opportunity to snatch away Eternity and the Shrive.
Having overcome the first test to the Key of the Abyss, we can now proceed onwards to face our second trial in the Halls of Doppelgangis.
- ↑ 1.0 1.1 Official Interplay Walkthrough: "Level One - Dominion: Vine, the major demon and Master of Dominion rules this level. To successfully traverse this level you must collect 'brains' and place them in the brain machine. This lowers the platforms to allow exit. Defeat Vine and the Power of Dominion is granted. This shields Adam from Illusions."