Six years after the Battle of Endor, Palpatine returned to threaten the New Republic. Unbeknownst to the Rebellion, the Emperor had maintained a secret supply of Spaarti cloning cylinders on the planet Byss in the Deep Core. Years before his death at Endor, Palpatine's body had begun to decay so rapidly from the ravaging dark side energies it contained that he had been forced to begin periodically transferring his soul into fresh clones of himself. Vader's treachery, however, had been unexpected, and the spirits of the ancient Dark Lords of Korriban had been forced to intervene and draw Palpatine back from the "madness beyond death" themselves. Palpatine's spirit, lacking a nearby clone body to inhabit, took possession of the Emperor's Hand Jeng Droga. Though Droga went mad in the process, he journeyed to Byss, where Grand Vizier Sate Pestage exorcized the disembodied Emperor, allowing him to possess a fresh clone. Unfortunately for the Sith Lord, spending such an extended period outside his body had driven the Emperor partially insane. Though he and his loyal Imperial forces managed to briefly retake the galactic capital of Coruscant and wreak havoc on the galaxy for a year, the mental health of the resurrected Palpatine continued to deteriorate due to his repeated deaths and the genetic tampering done to his clones by the treacherous Sovereign Protector Carnor Jax. He died a final death on the planet Onderon, when dying Jedi Knight Empatajayos Brand, a survivor of the Jedi Purge, bound the Emperor's departing life essence to his own, taking the Dark Lord with him as he became one with the Force. So Emperor Palpatine, Darth Sidious, arguably the greatest Dark Lord of the Sith, descended into eternal madness in the Chaos beyond death.
hough Jedi have continued to fall into darkness since then, none have proved as great a threat as that posed by the newest Sith Order. Lumiya, a former Emperor's Hand and Darth Vader's secret apprentice, became Dark Lady of the Sith following her master's death at Endor. She trained two apprentices: Flint, who was redeemed by Luke Skywalker, and Carnor Jax, who was killed by Palpatine loyalist Kir Kanos shortly after the Emperor's final death on Onderon. Afterwards, Lady Lumiya went into hiding, returning the Sith Order to the secret, underground existence begun by Darth Bane a millennium before.
Following the Yuuzhan Vong War, however, Jedi Knight Kyle Katarn encountered a Force-strong Yuuzhan Vong female in the mysterious Cloak of the Sith region of the galaxy, where it was rumored that post-Palpatine Sith still lived. Powerful though she was, Kyle sensed an even darker hand behind her training. Apparently, this Yuuzhan Vong had a Master . . .
Our relations with our neighbors have improved...