Mechanus

Mechanus is a plane of absolute order, usually pictured as endless interlocking gears.

Campaign 1. In the epilogue to The Skyfire, the construct NX467 finished rebuilding the shadow temple in The Shadowfell and returned to "the Clockwork Nirvana of Mechanus", where he eventually ascended to Decaton.

Campaign 2. In 1034 PC SAM sensed that his soul had been magically imbued and that Mechanus, the plane of mechanised souls, was speaking to him. After Shoshana sent the party to "seek out Guildmaster Elrithien" of The Star Scorpion Guild, they learned that the third part of Scribble's spell lay in Mechanus and plane-shifted there on Scribble's spell slot (C2 · Wednesday 19 April 2023 · Into Mechanus). They slipped past brain-busters into the guild's old outpost, which the astral elves called the Celestia Machina and the modrons the Genesis Forge (The Celestial Machina or the Genesis Forge). A window there looked out on The Astral Sea, though the forge lay miles below the surface of the plane. Paige read the decayed Elrithiens research journal, and the party took an amulet of the planes, a wand of binding, a clockwork scarab and a component to upgrade Olaf's visor before fighting scorpion guardians to reach Elrithien's tomb, whose epitaph invokes "the eternal clockwork of Mechanus". The party also suspected that Duhm was a former primus who had fled Mechanus after poisoning its pool.

Mechanus holds light and dark, heat and cold and the four elements in exact balance. Everything has its place, and its people exist to fit the greater scheme: there is no pain, and the only pleasure is filling a role well, like a gear in a machine. Passion, fantasy and illusion arrive only with visitors, and anyone stirring individualism or a cause is not well received.

SAM's journey (1034). Separately, SAM walked into Mechanus alone through a cursed artwork in Duskmere, reached Regulus, seat of the Primus, and learned that a goat-headed demon had killed the Primus and sat in its energy pool until sixteen years earlier, leaving a tainted successor. A marut banished him into the sea off Vistas Landing (SAM in Mechanus).

Reaching it. By a diamond colour pool in The Astral Sea, a white curtain in the Deep Ethereal or a plane shift fork of silver tuned to C.