In the original trilogy, Palpatine is depicted as the Emperor of the Galactic Empire and the master of Darth Vader (Anakin Skywalker).
Vader, the only power who overrules him is papa Palpatine. The reason why Vader obeyed tarkin was out of a sense of respect for him as a military leader, not as his superior.
Emperor Palpatine Protected Tarkin From Vader
Several times, Vader tried to get hostile with Tarkin, yet the Emperor always stopped Vader, and told him that Tarkin had full authority over him.
As Supreme Commander, Darth Vader was the ranking leader of the Imperial Military.
Tarkin was the commanding officer of the Death Star and had overall control of its operations. Vader was there as the Emperor's representative, and followed Tarkin's orders because it was Tarkin's command.
Regardless, Vader reported to Tarkin as Tarkin officially outranked him, as designed by the Emperor to limit his power within the Empire.
Kylo Ren is a fictional character in the Star Wars franchise. He first appeared as the primary antagonist of Star Wars: The Force Awakens (2015), in which he is portrayed by Adam Driver.
Darth Sidious
Darth Sidious is easily the most powerful Sith to ever live. He was able to almost single-handedly start a war, take control of the Senate, convert countless people including Anakin Skywalker to the dark side, overthrow the Jedi, and become emperor of the Galactic Empire.
During the early days of the Clone Wars, Skywalker served as a Jedi General in the Grand Army of the Republic, commanding the clone troopers of the elite 501st Legion against the Confederacy of Independent Systems.
Along with Jedi Commanders, clones with special training were given ranks of Commander to assist in leading the army. Later, Supreme Chancellor Palpatine was given ultimate command as the Supreme Commander.
Originally a slave on Tatooine, Anakin Skywalker is a Jedi prophesied to bring balance to the Force. He is lured to the dark side of the Force by Chancellor Palpatine (Darth Sidious) and becomes a Sith Lord, assuming the name of Darth Vader.
An intimidating mix of machine and man, Admiral Karius serves as Darth Vader's second-in-command on Mustafar. Stern and unforgiving, he intends to see to it personally that the captain of the Windfall doesn't survive their stay at Fortress Vader.
At the same time, the Chancellor revealed that he himself was a Sith Lord, Darth Sidious, and would train Anakin. Confused and conflicted, Anakin ultimately succumbed to Sidious' temptations. Rechristened as Darth Vader, he became an agent of evil.
In Star Wars Legends and Canon, Galen Marek (Starkiller) is the only Jedi (other than Obi-Wan Kenobi) to put a beat down on Darth Vader/Anakin Skywalker.
Aside from agility and telekinesis, Yoda could absorb and redirect Force attacks, like lightning. Because of his higher understanding, he would easily overcome Darth Vader in a fight, though that doesn't mean it wouldn't be a difficult battle.
The Force: As the Chosen One, Vader was immensely powerful and had an amazingly strong connection to the Force, stronger than any Force-user ever in existence. He also possessed the potential to according to Obi-Wan Kenboi become the most powerful light and dark side Force-Sensitive being in the history of the galaxy.
Jedi Master Yoda is the most powerful of them all. This should come as no surprise, as he was the head of the Jedi Order in the prequels and was revered for his abilities during the original trilogy. Yoda's power is unmatched and was a real threat to Darth Vader and the Imperials.
Biography. Legend had it that Yoda—a Jedi who became Grand Master—was trained by N'Kata Del Gormo.
By the time of the Invasion of Naboo, two hundred years after the Great Disaster, the still-living Yoda was the sole holder of the rank of Grand Master. Yoda had trained generations of Jedi for eight centuries, and continued as Grand Master through the Clone Wars.
Vader used his pain and anger to fuel his Dark Side powers, becoming one of the most powerful Sith ever and perhaps the most feared. He was the enforcer of the Empire, using his red lightsaber and black armor to strike fear into his enemies, becoming an instrument of terror to fight the Rebels.
Darth Sidious, also known as the Emperor and Supreme Chancellor Palpatine, is not just the evilest Sith in Star Wars (arguably in both canon and Legends) but the evilest villain overall, deemed so thanks to his irredeemable actions throughout the Skywalker saga and surrounding content.
He also took the deceased leader's name as his new last name (probably for street cred). Even though Kylo Ren uses a red lightsaber, harnesses the dark side of the Force, and wears a cape, he is not a Sith. Because of that, he can never hold the title of Darth.
Kylo Ren dies on Kef Bir (the ocean moon of Endor) shortly after Rey deals a mortal wound during a lightsaber duel on the wreckage of the second Death Star. Though Rey Force-heals him, saving his life physically, this blow, coupled with the memory of his mother and father, destroys the man known as “Kylo Ren” forever.
1. Emperor Palpatine. Darth Sidious infiltrated the heart of the Republic and twisted it into the Empire, sparked a terrible war that engulfed the entire galaxy in fire and ash, corrupted once-noble Jedi to his cause, and executed Order 66 to erase the Jedi Order from existence.