Mace Windu was a respected Jedi Master. He was known for his purple lightsaber and his skills in combat. He was part of the Jedi Council and was very cautious about the rise of the Sith. He had his doubts about Anakin Skywalker and was eventually killed by Palpatine during the fall of the Jedi Order.
Sure. Let's take Darth Vader for example. He was once Anakin Skywalker, a Jedi with great potential. But his fear of losing his loved ones, especially his mother's death and his premonition about Padmé, led him to the Dark Side. The Sith Lord Palpatine manipulated him, and in a fateful duel with Obi - Wan Kenobi, he was severely injured and transformed into Darth Vader, serving the Empire ever since.
Rey is very important. She's a strong Force - user. Finn, who starts as a stormtrooper but defects, is also key. And Kylo Ren, the conflicted villain. In Star Wars 8, Luke Skywalker is crucial as Rey's mentor for a while. In Star Wars 9, they all play major roles in the final battle for the galaxy.
Luke Skywalker is definitely important. His journey as a Jedi in training and his role in the Rebellion is central.
Emperor Palpatine is crucial. He is the mastermind behind the Empire's rise. Darth Vader, his Sith apprentice, is also very important. He is a fearsome warrior. Grand Moff Tarkin is another significant character. He commands the Death Star.
One important character could be a Mirialan Jedi Master. This character would be wise in the ways of the Force and guide younger Mirialans or other species in their Jedi training. Another could be a young Mirialan Padawan, full of enthusiasm and a bit of naivete, learning the ropes of being a Jedi.
Obi - Wan Kenobi is obviously the most important character. He is the central figure around which the story revolves. Darth Vader is also crucial as his nemesis. There are also some local characters on Tatooine like Owen Lars who play important roles in Kenobi's life during his exile.
Anakin Skywalker and Obi - Wan Kenobi are the most important characters. They are the heart of the story as it focuses on their relationship and their growth as Jedi.
Ahsoka herself is of course the most important character. She is the central figure around which the story revolves. There are probably also characters from her past in the Jedi Order who play significant roles, like Anakin Skywalker, who was her master.
Obviously, Dooku himself is a crucial character. He is the central figure around which the story revolves. Count Dooku is a complex character who transitions from a Jedi to a Sith. Another important character is Yoda. His relationship with Dooku, as his former master, adds depth to the story.
The Mandalorian himself is of course very important. And then there's The Child (Baby Yoda), who is a central figure. Greef Karga, the leader of the Bounty Hunters' Guild, also plays a significant role. There are also Imperial characters like Moff Gideon who are important as antagonists.