Another idea is that Anakin falls to the dark side and kidnaps Ahsoka. He wants to train her in the ways of the dark side against her will. Ahsoka has to fight not only Anakin's dark side powers but also the temptation that the dark side presents to her in order to escape and return to the light.
One plot idea could be that Anakin, already on the dark side, tries to convince Ahsoka to join him. He shows her the power that the dark side can offer, like how quickly she could gain the ability to defeat her enemies. But Ahsoka is conflicted as she still has a strong bond with the light side teachings of the Jedi.
Maybe in the fanfiction, a dark side entity corrupts Anakin and Ahsoka at the same time. They start to carry out dark deeds together, like attacking Jedi temples. However, as they go deeper into the dark side, they start to have doubts and memories of their former selves start to resurface, creating an internal struggle.
One plot idea could be Anakin, in his darker state, being forced to team up with Ahsoka to face a common enemy. They have to overcome their differences and Anakin has to fight his inner demons not to harm Ahsoka. Another could be a time - travel plot where Ahsoka goes back in time and tries to prevent Anakin from fully turning to the dark side.
A possible plot could involve Ahsoka being betrayed by someone she trusts deeply within the Jedi or among her friends. This betrayal could be so severe that it pushes her over the edge, and she turns to the dark side for revenge. She then uses her newfound dark side powers to seek retribution against those who wronged her.
One idea could be that Anakin's fall to the Dark Side causes him to try and make Padme a Sith as well. He might use his newfound power to manipulate her, believing that together they could rule the galaxy. For example, he could start by isolating her from her friends and allies in the Jedi Order and the Republic, making her more dependent on him.
One idea could be that they meet during a time - traveling accident. They end up in a different era of the Star Wars universe and have to figure out how to get back while also dealing with the challenges of that era.
A fanfiction could explore a scenario where Anakin has a premonition about Ahsoka's future. He then tries to change her path in a way that challenges their relationship and the Jedi Code.
Maybe Ahsoka gets captured by a dark side cult. They try to convert her by showing her their version of 'justice' through the dark side. They expose her to their cruel and efficient ways of dealing with enemies, which makes her question her Jedi teachings. However, she eventually realizes that their 'justice' is just tyranny in disguise.
One idea could be Ahsoka being corrupted by the dark side due to a powerful Sith artifact she discovers. She starts to use her skills for her own gain, causing chaos in the galaxy. Another could be her being manipulated by a hidden Sith Lord who convinces her that the Jedi way is wrong. Maybe she forms her own dark order, recruiting those who feel betrayed by the Jedi or the Republic.
A possible plot could be that an enemy uses dark magic or some Sith - related power to make Ahsoka pregnant as a way to disrupt the balance. Anakin then has to find a way to reverse the spell while also protecting Ahsoka from those who would harm her because of this. Or perhaps it's a story of prophecy where their child is foretold to be a great savior or a great threat, and they have to deal with the expectations and fear that come with that. Also, it could be a story where Ahsoka gets pregnant accidentally and they struggle with the decision of what to do, considering their roles as Jedi.
One plot idea could be Ahsoka discovers Anakin's relationship with Padme and has to keep it a secret while also trying to protect them from the Jedi Council's potential discovery. Another could be a story set during a dangerous mission where Anakin and Padme are in peril, and Ahsoka must use her skills to rescue them. A third idea is a fanfic that explores how Ahsoka's presence in Anakin's life affects his relationship with Padme, whether it brings them closer or causes some unforeseen tensions.
One interesting 'dark side Ahsoka fanfiction' could be about her being corrupted by an ancient Sith artifact. She might start to use her skills in a more menacing way, turning against her former allies. For example, she could use her lightsaber skills to hunt down Jedi who oppose her newfound dark side ideology.