Star Wars comic revealed the Jedi possessed the secret of Sith resurrection - but never realized it. Force Ghosts are only the province of the light side of the Force, and the Sith have long coveted this power for themselves. Matt Stover's novelization of Star Wars: Episode III - Revenge of the Sith makes that explicit, in an extended conversation between Qui-Gon Jinn's Force Ghost and Master Yoda that was written in consultation with George Lucas himself. "The ultimate goal of the Sith, yet they can never achieve it," Qui-Gon explained. "It comes only by the release of self, not the exaltation of self. It comes through compassion, not greed. Love is the answer to the darkness."

It's long been clear Palpatine sought the secret of immortality during the Dark Times when the Empire reigned. Ultimately, the solution lay in the teachings of his master, Plagueis, who had taught his apprentice how to transfer his essence to another vessel at the moment of death. Palpatine continued to research this technique when he became Emperor, and the key lay in the ancient mask of Darth Momin, a Sith heretic who had transferred his spirit into his mask before it was lost to the netherworld.

Related: Star Wars Confirms The First Jedi DIDN’T Serve The Light Side

Ironically, it seems that the Jedi Order were the ones who possessed the mask of Darth Momin. A brief scene in 2017's Darth Vader #8 by Charles Soule and Giuseppe Camuncoli shows Jocasta Nu, Jedi Archivist, enter a secret storeroom in the Jedi Temple where she kept her most sacred artifacts. The Jedi had entrusted Jocasta Nu with items they had trusted no other Jedi to keep, including Sith Holocrons and - crucially - the mask of Darth Momin.

Star Wars Darth Momin Mask

Jocasta Nu was hardly the most powerful Jedi, but she was the one Jedi Palpatine feared. The Sith Lord believed all the secrets of the Sith and the Jedi were known to her. If that is indeed the case, then she alone knew the Sith could survive after death. The intriguing possibility is that she left a record of this because she survived Order 66 and created Holocrons containing all her knowledge to help ensure the Jedi would one day return. These Holocrons were ultimately found by Luke Skywalker himself - meaning Luke could actually have known about essence transfer. What secrets did Luke Skywalker suspect he was going to uncover when he sought the Sith planet Exegol?

This adds a fresh layer of irony to Star Wars: Episode III - Revenge of the Sith, because in one scene Palpatine teased Anakin Skywalker with the knowledge of how to conquer death. He told the Jedi the legend of Darth Plagueis the Wise and ended by telling him it was not possible to learn this power from a Jedi. Ironically, the Sith Lord probably suspected there was actually one among the Jedi who could have told Anakin about essence transfer - but, of course, Jocasta Nu would never have done so, and essence transfer would have been useless to save Padmé's life anyway, because the power only allows the Sith Lord themselves to survive after death.

The mask of Darth Momin would go on to play a crucial role in galactic history. Palpatine learned its secrets, and he subsequently gave it to Darth Vader himself; Momin had been a Sith architect, and Vader had him design his fortress on Mustafar in order to manipulate the Force vergence of that world in an attempt to resurrect his beloved Padmé - but it went badly wrong, with Momin attempting to resurrect himself instead. No doubt accounts of Momin's brief new lease of life would have pleased the Emperor, telling him he was on the right track with essence transfer - and helping the greatest villain of Star Wars to return.

More: Star Wars: Everyone Who Knew Palpatine Was a Secret Sith Lord