This is probably a stupid idea since Ahsoka is really too much of a follower of the Jedi code but sometimes its like she really just follows Anakin. Seriously, half the time she is just a miniature him. So this is my take if Ahsoka turned to the darkside in her naivety.
Disclaimer: I don't own Star Wars
Ahsoka woke to an unfamiliar mechanical breathing in the med after being unconscious for a month. She did not open her eyes as she tried to remember what had happened. She remembered seeing the troopers in front of her being killed and their screams. She remembered being thrown back but that was all.
She slowly began to part her eyes and the light began to pour into her blurred world. She blinked a few time before realized where she was. She looked up and saw a droid looking down at her. No wait, she could feel it through the force. Then she realized that it was a person and not just any person but her master. In a weak voice, she asked,
"Yes, it is me."
"What happened to you? Who did this?"
"All in good time. Right now you need to rest. You were hit pretty hard by that piece of shrapnel. You've been out for almost a month."
"Master if I have been out for almost a month then I don't need to rest. Now tell me what happened to you. I can't feel you completely in the force and you don't feel quite right."
"Ahsoka, listen carefully. The Jedi have turned against the Republic."
"No, that can't be true."
"It is Ahsoka. Look."
Vader held up a small holoprojector and showed Mace Windu trying to kill Palpatine and the last part of the fight scene between him and Obi-wan except, though Ahsoka did not know this, the part where Obi-wan said he had loved Anakin as a brother had been omitted. Ahsoka gasped as she saw Obi-wan cut her master and by the end of the holovid, she had tears in her eyes.
"Do you see now, Ahsoka?"
Ahsoka simply nodded. She could feel the darkside in her master but she decided that master knew best.
"Good. I knew I trained you well. We will restore peace to the galaxy. You shall become a Sith as I have."
"But master, Yoda always said that"
"Snips, the Jedi have been lying to everyone and I am ashamed I followed them. We have not been fighting the darkside at all. The Jedi have been teaching us the darkside and keeping us away from the lightside. Do you understand?"
"No, you don't really but you will in time. Come with me."
Vader extended his mechanical hand to Ahsoka. She looked at it and back at the mask of her master. She knew this went against everything she had been taught but trusted Anakin with her life and he cared about her. She was the padawan of the Chosen One and if the Chosen One had found a way to bring balance to the force then she would follow.
Ahsoka got out of the bed and put her small, orange red hand in to his gloved one. She took her first step into darkness. It felt so wrong yet at the same time it felt right to be following her master. She really didn't know what she doing just that she needed to follow her master.
Yes, she did trust Anakin with her life but little did she know that the thing in front of her was not Anakin. It was almost a completely different person. It was the remaining bits of Anakin's but more so it was the beginning sprout of the one of the most feared villains.
It was Vader. Darth Vader
I know it was short but that is how I write sometimes. I may just keep this as a one-shot but I was thinking about making it a multi-chapter fanfiction. Actually that was my initial idea but its up to you guys. So please review.