He is Darth Vader's master and was secretly Dark lord of the Sith but people knew him as (Senator) Palpatine. He is also referred to as The Emperor.
Emperor Darth Sidious, also known as Sheev Palpatine, is a fictional character in the Star Wars franchise. He is a Sith Lord who rises to power as the Emperor of the Galactic Empire and is the main antagonist in the original and prequel trilogies. Sidious is known for his manipulative and cunning nature, as well as his mastery of the dark side of the Force.
He IS the Emperor!
Darth Vader's Master is technically the Emperor when he was a Sith, but when he was training as a Jedi his master was Obi-Wan Kenobi
Count Dooku was trained as a Sith by Darth Sidious, also known as Emperor Palpatine. Darth Sidious was responsible for turning him to the dark side and giving him the Sith name Darth Tyranus.
Darth Sidious
Darth Sideous' alter ego is Emperor Paltapine.
No, he does not. Darth Vader's first apprentice (Galen Marek/Starkiller) is killed by Emperor Palpatine/Darth Sidious.
Darth Sidious appears in the first Star Wars trilogy. In the original trilogy he is Emperor of the Galactic Empire. He then also appears in the prequel Star Wars trilogy.
Darth Sidious is known to the majority of the galaxy as Emperor Palpatine. Before he became the emperor he was a senator from Naboo, so he was known as Senator Palpatine. When he ascended to the chancellorship of the Senate, he became known as Chancellor Palpatine.
Throughout the six movies, Chancellor Palpatine aka Darth Sidious is the main antagonist. Each individual movie has its own resolved antagonist as well. Episode 1: Darth Maul Episode 2: Darth Tyranus aka Count Dooku Episode 3: General Grievous Episode 4-6: Darth Vader and Emperor Palpatine (Darth Sidious)
I suppose this is more of an opinion question if you're asking about the characters' personalities, but power-wise, Darth Sidious is much stronger and far more cunning than Savage Opress.
Darth Sidious was. Not really a boss, but a master and/or a mentor. He was also the "chancellor" during episodes 1-3 and the clone wars. Sidious was also the most powerful Sith.
Darth sidious