AHSOKA: I was beginning to believe I knew who you were behind that mask, but it's impossible. My master could never be as vile as you.
VADER: Anakin Skywalker was weak. I destroyed him.
AHSOKA: Then I will avenge his death.
This is obviously in a much more philosophical and metaphorical sense; same as Obi saying Vader killing Anakin was true "from a certain point of view". I mean... she saw the goddamn vision of Anakin becoming Vader; Tano's either in some serious denial or she knows, but doesn't wanna admit it out loud.
For Vader, for Ahsoka she believed him. That's very obvious from her reaction. And she says from the beginning that she thinks him being Anakin is impossible, lel, a hallucination she had isn't exactly the most concrete of proof to the contrary.
Moreover, the attitude she takes when she realises it is in fact Anakin, is entirely different to before.
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Last edited by Beniboybling on Mar 20th, 2017 at 06:19 PM
Contrast her attitude before the fight started and then her reaction after the fight ended when he called out to her, and it's clear that she at least wasn't really consciously accepting of the fact until the end -- either that or she just didn't think it was Anakin, flat-out. I doubt she would've tried to behead him if she was like "yeah, that's totally Anakin."
Also, it's pretty hilarious how everyone wants to point out how Ahsoka supposedly had an advantage over Vader because she was his apprentice and knew his form, but they conveniently ignore the fact Vader was the person who actually trained her to fight and would therefore at the very least cancel her "advantage" out. And you gotta love how the same people who mention Ahsoka knowing Vader's form as a means of discrediting her feat are the same people who routinely deepthroat Kenobi's performance against Vader on Mustafar, despite that fight being a much more extreme example of form familiarity playing a role in combat.
__________________ ''It is necessary that I should die for my people; but my spirit will rise from the grave and the world will know that I was right." The Almighty Führer