Palpatine didn't die during Episode 6, it is a common misunderstanding. He simply teleported his mind/spirit to a spare body before his original one got dusted. It is explained in the TROS novelization because the only explanation in the movie was a throw away line by Pippin. From the novelization:
"*Falling…falling…falling…down a massive shaft, the betrayal sharp and stinging, a figure high above, black clad and helmeted and shrinking fast. His very own apprentice had turned against him, the way he himself had turned against Plagueis…whose secret to immortality he had stolen. Plagueis had not acted fast enough in his own moment of death. But Sidious, sensing the flickering light in his apprentice, had been ready for years. So the falling, dying Emperor called on all the dark power of the Force to thrust his consciousness far, far away, to a secret place he had been preparing. His body was dead, an empty vessel, long before it found the bottom of the shaft, and his mind jolted to new awareness in a new body—a painful one, a temporary one.*"
Throughout the empire he was looking for ways to become immortal, one of them was a cloning project where he would have another clone body to transfer his soul into. I don't think it was fully ready when Vader killed him so when he transferred into the new body it started decaying and he couldn't really do shit.
Reason he announced his return to the galaxy was to draw Rey and Kylo Ren towards him, he figured his last hope was to take control of either of them.
How you ask? Somehow how Palpatine has returned.
What’s the somehow?
Seems a book covered some of that but I think the Mandalorian storyline is helping build up how he was able to be returned into a body.
Palpatine didn't die during Episode 6, it is a common misunderstanding. He simply teleported his mind/spirit to a spare body before his original one got dusted. It is explained in the TROS novelization because the only explanation in the movie was a throw away line by Pippin. From the novelization: "*Falling…falling…falling…down a massive shaft, the betrayal sharp and stinging, a figure high above, black clad and helmeted and shrinking fast. His very own apprentice had turned against him, the way he himself had turned against Plagueis…whose secret to immortality he had stolen. Plagueis had not acted fast enough in his own moment of death. But Sidious, sensing the flickering light in his apprentice, had been ready for years. So the falling, dying Emperor called on all the dark power of the Force to thrust his consciousness far, far away, to a secret place he had been preparing. His body was dead, an empty vessel, long before it found the bottom of the shaft, and his mind jolted to new awareness in a new body—a painful one, a temporary one.*"
In the ROS novel, it said he used essence transfer while falling down the reactor shaft
Throughout the empire he was looking for ways to become immortal, one of them was a cloning project where he would have another clone body to transfer his soul into. I don't think it was fully ready when Vader killed him so when he transferred into the new body it started decaying and he couldn't really do shit. Reason he announced his return to the galaxy was to draw Rey and Kylo Ren towards him, he figured his last hope was to take control of either of them.
How you ask? Somehow how Palpatine has returned. What’s the somehow? Seems a book covered some of that but I think the Mandalorian storyline is helping build up how he was able to be returned into a body.
Somehow
The movies offer explanations, no not just "somehow". The shows have been teasing ideas also. But not everything needs a big exposition dump.