"The Dark Side of the Force is a pathway to many abilities some consider to be un-natural..."
— Supreme Chancellor Palpatine
General Grievous: You Fool! I have been trained in your Jedi arts by Count Dooku.
Obi-Wan Kenobi: It's funny you should mention that. I trained the man who killed him.
— The novelization
Mace Windu: In the name of the Galactic Senate of the Republic, you're under arrest, Chancellor.
Supreme Chancellor Palpatine: Are you threatening me, Master Jedi?
Windu: The Senate will decide your fate.
Windu: Not yet.
"Once more, the Sith shall rule the galaxy! And we shall have... peace."
— Darth Sidious
Darth Sidious: Commander Cody. The time has come. Execute Order 66.
Cdr. Cody: It shall be done, my Lord.
Obi-Wan Kenobi: It's over, Anakin. I have the high ground!
Anakin Skywalker: You underestimate my power!
Obi-Wan: ...don't try it.
Obi-Wan: YOU WERE THE CHOSEN ONE! You were meant to destroy the Sith, not join them! Bring balance to the Force, not leave it in darkness.
Darth Vader: I HATE YOU!
Darth Sidious: Lord Vader. Can you hear me?
Darth Vader: Yes, master... where is Padmé? Is she safe? Is she all right?
Sidious: It seems, in your anger... you killed her.
Vader: I... I couldn't have. She was alive! I felt it!
(Vader, through the Force, destroys the equipment of the laboratory he's in)
"The dark is generous, and it is patient, and it always winsóbut in the heart of its strength lies weakness: one lone candle is enough to hold it back. Love is more than a candle. Love can ignite the stars."
And there is one blazing moment in which you finally understand that there was no dragon. That there was no Vader. That there was only you. Only Anakin Skywalker.
That it was all you. Is you.
You did it.
You killed her.
You killed her because, finally, when you could have saved her, when you could have gone away with her, when you could have been thinking about her, you were only thinking about yourself...
It is in this blazing moment that you finally understand the trap of the dark side, the final cruelty of the Sith—
Because now your self is all you will ever have.
And you rage and scream and reach through the Force to crush the shadow who has destroyed you, but you are so far less now than what you were, you are more than half machine, you are like a painter who has gone blind, a composer gone deaf, you can remember where the power was but the power you can touch is only a memory, and so with all your world-destroying fury it is only droids around you that implode, and equipment, and the table on which you were strapped shatters, and in the end, you cannot touch the shadow.
In the end, you do not even want to.
In the end, the shadow is all you have left.
Because the shadow understands you, the shadow forgives you, the shadow gathers you unto itself—
And within your furnace heart, you burn in your own flame.