In the fanfic, Arya might kill Joffrey during a big event. She could blend in with the chaos. Since she has great agility and combat skills, she could quickly approach Joffrey while everyone is distracted. For example, during a tournament or a grand feast. She could jump from a balcony or some hidden place, stab him swiftly, and then disappear into the crowd before anyone realizes what has happened.
There would be chaos. Joffrey is a king, so his death would create a power vacuum. His mother Cersei would be furious and would likely start a manhunt for Arya. The Lannisters might declare war on Arya's family or allies. The political landscape would be completely disrupted as different factions would try to take advantage of the situation.
In the fanfiction world, Ned Stark might kill Littlefinger if he discovers Littlefinger's true manipulative nature early on. Maybe he finds proof of Littlefinger's role in some of the political schemes that are endangering his family. Ned is an honorable man, and once he has evidence of such treachery, he would not hesitate to dispense justice.
In the official 'Game of Thrones' series, it was Sansa's necklace (which was actually a poisoned device) that led to Joffrey's death, not Arya. However, in some fanfics, authors might create alternate storylines where Arya kills Joffrey. But these are non - canonical and just creative interpretations by fans.
She could use her Faceless Men skills. Maybe she disguises herself as one of the serving staff. Since she has been trained to blend in and move unnoticed. She could then poison the wine or food that was meant for the main players in the Red Wedding. This way, she can stop the massacre before it even starts.
If Arya killed Joffrey in a fanfic, one possibility is that she would become an instant target for the Lannisters. They would stop at nothing to avenge Joffrey's death. Arya would have to go into deeper hiding or rely on her Faceless Men training even more. Maybe she'd have to flee across the Narrow Sea and start a new life in Essos, constantly looking over her shoulder for Lannister assassins.
A fanfic involving a Dragonborn in the Game of Thrones universe with Joffrey could be a wild ride. Maybe the Dragonborn, with their dragon - riding abilities and magic, would pose a significant threat to Joffrey's tyrannical rule. They could swoop in on their dragon, causing chaos in King's Landing and challenging Joffrey's claim to the throne.
Arya's character development might be shown in her post - kill actions. After killing Walder, she doesn't just run away. Instead, she takes control of the situation. Maybe she installs a more loyal or just leader in his place. This shows that she is not just out for revenge but also has an idea of how to restore order in the places that have been wronged by the likes of Walder. It also shows that she has matured from a simple seeker of vengeance to a more complex figure with a sense of leadership and justice.
The twin could be a long - lost relative of Arya. Maybe they are from a branch of the Stark family that was thought to be dead or lost. This would add an interesting layer to the story as they would share some of the Stark blood and loyalty.
There could be a really interesting fanfic where a Dragonborn enters the world of Game of Thrones during Joffrey's reign. Maybe the Dragonborn would initially be seen as a threat by Joffrey. But the Dragonborn's powers could change the power dynamics in King's Landing. For example, if the Dragonborn has the ability to control dragons, it would be a huge advantage over the Lannisters who rely mainly on their wealth and military might at that time.
In the context of the fanfic, the Dragonborn's presence could also expose Joffrey's weaknesses more clearly. The people of Westeros, seeing someone with such great power (the Dragonborn) who is not as cruel as Joffrey, might be more inspired to rise up against Joffrey. And Joffrey's own allies might start to question their loyalty to him when they see the Dragonborn as a potential new power player in the game of thrones.