What would have happened if Regulus Black survived in fanfiction?

Well, if Snape survived, he might have found some peace and redemption. Maybe he would have continued teaching and guiding the younger wizards with a new perspective.

If Padme survived, it's likely she would have been a powerful force for good. She could have supported Luke and Leia in their own destinies and helped them avoid some of the challenges they faced. Maybe she would have even united various factions against common enemies.

It could lead to a whole new power struggle within the Empire. Maybe Vader would try to reform it or take it over completely.

If Bella survived, it might have changed the dynamics within the vampire clan. There could have been more power struggles or maybe she would have found a way to bridge the gap between vampires and humans. It would definitely open up a whole new world of possibilities for the story.

Sirius would probably be angry at first in the fanfiction. He left his family and Regulus was still part of it. But as the story progresses, he might start to feel some regret or longing for his brother. James would be supportive of Sirius' emotions, and Remus would be the voice of reason, analyzing Regulus' actions and motives.

It could have changed Anakin's entire path. Maybe he wouldn't have turned to the dark side as quickly or at all.

She might have access to unique Black family resources. For instance, she could find a hidden Black family library filled with dark arts books (which she would use for good, of course). This would give her an edge in her studies and in fighting the Dark forces.

A fanfiction with this premise might explore how Regulus changes Hufflepuff. His Slytherin upbringing could bring in a different perspective. He might introduce new ways of thinking about magic and the wizarding world to his Hufflepuff housemates. For instance, he could have a more cut - throat approach to Quidditch (a Slytherin trait) which could initially shock the Hufflepuffs but then inspire them to be more competitive in a healthy way. At the same time, Hufflepuff's values start to change him too, making him more open - hearted and less concerned with pure - blood status.

Well, if Jon Snow never took the black, his path would have likely been very different. Maybe he would have stayed at Winterfell and had a greater role in the affairs of the North.

He might be quite surprised. Fanfiction often takes the original story in new and unexpected directions. He could be intrigued by different interpretations of his own character or the events at Hogwarts.