Recap
In the Feywild with Aunty Suzie, the party looked over a dwarven city shrunk inside a terrarium of residuum, building an army of machines. The bubble feels cold to humans and hot to mechanical beings and fiends. Xosomasaux's coat, a star-elf relic made by Guildmaster Elrithien, let them reach through it; the party watched modrons and war machines being built inside, and "introduced nukes to the dwarves in the bubble". Shoshana told them to "seek out Guildmaster Elrithien" of The Star Scorpion Guild, long dead, who also made Olaf's visor.
The third part of Scribble's spell lay in Mechanus, so the party plane-shifted there on Scribble's slot, slipped past brain-busters and entered Elrithien's tomb (The Celestial Machina or the Genesis Forge). Paige read a decayed book, Elrithiens research journal: automatons, the Arcane Loom, the Soul Luxon as a reincarnation cycle for machines, infernal clients, the Ashen Covenant commissioning a visor, and the guild hiding from the Covenant that the automatons had become sentient. A hidden compartment held an amulet of the planes, a wand of binding, a clockwork scarab and a component that upgraded Olaf's visor into The Visor of Fathoms. The party fought scorpion guardians to enter the grave proper, where Olaf saw through the walls a body in the coffin with one mechanical hand and leg. They also had a ring of truth-telling and a luckstone to divide.