One of the things that we know about the world of Star Wars is that the Jedi Order has long been at war with the Sith Order.

Little has been revealed about Darth Sidious former master, the Sith Lord Darth Plagueis, in Star Wars canon. This is everything we know so far.

Darth Sidious was born in Naboo, 36 years before the birth of Anakin Skywalker, who would later, devastatingly, ... He gained all of his master's knowledge, then killed him, ...

Darth Plagueis is dead. He has been dead since Darth Sidious killed him, rising to the rank of master in the Sith, as told in 2005’s Star Wars: Episode III – Revenge of the Sith.

Seeing what his master was achieving inspired Darth Sidious to murder Plagueis in his sleep – something Plagueis was too distracted (by his quest for power and immortality) to see coming.

The inclusion of Darth Plagueis in Star Wars: The Acolyte is a topic of much speculation among fans. At the time of writing, there has been no official confirmation about his appearance in the series.

Darth Maul almost never became Darth Sidious’s apprentice. In the Star Wars universe, the Sith almost always come in two. As Yoda told Mace Windu in The Phantom Menace , “Always two, there are.