Palpatine was by no means helpless after being disarmed by Mace Windu, as shown with his onslaught of Force lightning. As described in the Revenge of the Sith novel, Palpatine was slowly pushing Windu's lightsaber blade towards him and could have killed him with his own weapon if he persisted.
If he did there would be no point of the OT or the ST for that matter. Ironically, if Windu did kill him and become possessed, Palpatine's own machinations would backfire as he'd now be public enemy #1 and completely lose his decades of political protections.
Darth Vader. Mace Windu can obviously put up a somewhat decent struggle, but he can't win, nor is he Vader's equal. Basically, Mace Windu might have two advantages against Vader, his Vaapad and his shatterpoints awareness, not only against Vader, but against most darksiders in general.
As the war continued, Mace came increasingly to distrust Palpatine -- though he never guessed that the Supreme Chancellor was in fact the Sith Lord Darth Sidious.
What if Anakin WENT With Mace Windu To Fight Palpatine?
Was Mace Windu a grey Jedi?
The term “gray Jedi” in Star Wars is somewhat of a misnomer, considering that the definition refers to one who is practically non-Jedi. That being said, quite a few Jedi can be placed into this category. But Mace Windu identified as a Jedi despite his possible inclusion in the "gray" category.
Only three Jedi/Sith in Windu's lifetime ever surpassed him, (Darth Sidious, Master Yoda, and Anakin Skywalker) and all three just so happened to be candidates for “most powerful Force-User in the Republics' 25,000 year history” at various times.
Though seemingly unbeatable, General Grievous famously met his end on Utapau, thanks to Obi-Wan, and was previously defeated by Mace Windu during the Battle of Coruscant, but Windu had also bested Grievous one other time, as shown in issue 5 of Star Wars: Obsession, by Haden Blackman and Brian Ching.
Infil'a put up a fierce fight against Vader, almost killing him by throwing the already damaged Sith Lord off of a cliff. Despite severe damage to his suit, Vader survived the fall, and repaired himself with parts from Infil'a's droid, Arex.
Sadly the Clone Wars would have still happened, but Padmé would have also survived, giving birth to Luke and Leia who would have probably been inducted into the Jedi Order. As for what would have happened between the two, with their marriage and all, that's a bit tricky.
What would have happened if Anakin killed Palpatine?
The Clone Wars only ended when Palpatine sent Darth Vader to assassinate the Separatist Council and shut down their droid forces. Without Palpatine, the Separatists would continue to plague the galaxy, even with Dooku and Grievous dead.
If the two spared as Jedi, Dooku would probably win the match because he was the better all-around duelist. But if this issue's fight had continued with Windu as a Sith, Windu would have been able to turn the tables.
Windu has created and fully mastered Vaapad, a variant of Form VII. Yoda mastered the original variant known as Juyo. Both of them were able to fight with Palpatine on equal ground, matching him blow for blow. It is stated that Yoda beat Mace in a sparring match.
Originally Answered: Is Mace Windu alive in the Star Wars universe? Canonically no, he was declared dead by Lucasfilm after Sidious shot him out the window 3,000 stories off the ground.
Dooku did actually beat Windu in a lightsaber duel back when he was still a Jedi. In fact, the only two Jedi in the entire Order to ever beat Windu were Dooku and Yoda.
Mace Windu vs Darth Maul | Fandom. Mace windu clear winner 9/10 times. His use of vapad would make the fight play out similair to windu vs palpatine. He would use the seething rage pouring out of maul against him, and as mauls force power was so much weaker than windu's it would be an undisputed win for windu.
There are certainly scenarios where Darth Vader would have the upper hand in a duel with Yoda, but in most cases, Yoda would be the more likely victor. Vader wields absurd levels of Force power during his dark side prime that would certainly rival Yoda's own abilities, but likely not exceed them.
Once he became Darth Vader, Anakin had long become superior to Dooku and Mace Windu. He exceeded their power while still living as Anakin Skywalker, and greatly exceeded their power later in life, both in the force and in lightsaber combat.
Look, he definitely isn't Mace Windu's son: the age doesn't match, considering the other character's ages (Luke, Leia, Vader, Solo, etc.). However, i think it's possible to see Finn as his grandson, but for that you must consider that Windu had a secret baby close to his time of death.
The following year, a Duros sold a broken lightsaber, which he claimed once belonged to Master Windu, to Senator Sano Sauro. Though the claim was never verified, Senator Sauro displayed the lightsaber in question in his office.
Mace Windu appears as a Force ghost in the alternate history comic Star Wars Infinities: The Empire Strikes Back in a vision to Darth Vader, though this may only be a mental vision in Vader's mind as opposed to an actual Force ghost.
