There could be a hermit or an outcast Jedi or Sith on Dathomir. Anakin meeting this character could lead to a great revelation. Maybe this character has been in hiding on Dathomir for years, observing the balance of the Force there, and Anakin's arrival disrupts that balance and forces an interaction that changes Anakin's perspective on many things.
He could interact with Luke Skywalker. Imagine Anakin finally getting to meet his son as an ally in the Rebellion. They could train together and share their knowledge of the Force.
Anakin could be angry. He might see his other self as a threat, especially if one represents his dark side and the other his light side. There could be a power struggle between the two versions of himself as they try to assert dominance over the other. Or he could be curious and eager to learn from his other self, about what he could have been or what he can still become.
Anakin could encounter future versions of his friends or enemies from the past. For instance, he could run into a future version of Obi - Wan Kenobi who has also somehow traveled to that future time. Or perhaps he meets a new generation of Sith who have different motives and methods compared to the Sith he knew in his own time. They could challenge his understanding of the dark side and the Force in general.
Anakin would be completely shattered. Ahsoka was one of the few people he truly cared about deeply. Her death in his arms would make him question his abilities as a Jedi and a protector. He might feel a deep sense of rage towards whatever or whoever caused her death, which could start to cloud his judgment and lead him down a darker path.
If that were the case, the galaxy's fate would likely have been very different. Maybe they could have avoided the conflicts and tragedies that came with Anakin's Jedi path. But who knows how other forces would have shaped events without the Jedi's influence.
In fanfic, Anakin Solo is often depicted as brave. He faces numerous dangerous situations without hesitation. For example, in some fanfics, he bravely confronts new threats to the galaxy.
I'm not entirely sure specifically what a particular 'anakin shower fanfic' is about as it could vary greatly depending on the author's imagination. It might involve Anakin Skywalker in a scenario related to a shower, perhaps some self - reflection, a moment of relaxation, or some sort of encounter within the context of that setting.
In some fanfics, it could be Anakin's own self - destructive tendencies. He has made so many bad choices in his life that in the end, his own actions lead to his death. For example, if he continues to pursue the dark side without fully understanding its consequences, it could ultimately consume him and lead to his demise.