Kaguya could be a great antagonist. Even though she was defeated in the main Naruto story, she could be resurrected or have some lingering influence. Her power - hungry nature and her desire to control everything could put her at odds with Indra and Asura, who are symbols of two different paths in the ninja world. She might try to manipulate them to further her own goals or eliminate them as threats to her reign.
One idea could be exploring their relationship in a modern AU. Imagine Indra and Asura as two brothers in a modern city, dealing with normal life problems while still having their spiritual connection. They could struggle with family expectations, like Indra being the over - achieving older brother and Asura the more laid - back one, but they have to come together to face a common threat that has a connection to their past lives.
Often, other characters from the Naruto universe also make appearances. For example, the various ninja clans like the Uchiha and the Senju. Their loyalties and relationships with Indra and Asura can add depth to the story. Maybe there are also some original characters created by the fanfiction writer to interact with Indra and Asura and drive the plot forward in unique ways.
A fascinating plotline could be that Indra and Asura are sent on a journey through different dimensions by some ancient jutsu. In these dimensions, they see different versions of themselves and their story. They learn from these experiences and come back to their world with a new perspective, which could potentially change the course of the Naruto universe.
A fanfic could focus on a time - travel plot. For example, Asura or Indra gets sent to a different era and has to adapt while also finding a way back. Along the way, they encounter versions of themselves or each other from that time and have to deal with the consequences of interfering with the timeline.
By showing their shared history. Maybe start with a flashback of their childhood together, how they were friends or rivals from the start. This can set the foundation for their complex relationship in the present of the fanfic.
One interesting idea could be the exploration of how the reincarnation affects Naruto's relationships. For example, how it changes his bond with Sasuke, as Sasuke is often linked to Indra. Maybe it could lead to a deeper understanding between them, beyond their normal rivalry.
Madara could also be a suitable antagonist. Imagine if he somehow came back to life and found out about Asura and Indra's reincarnation. He would surely try to use them for his own goals, or maybe try to prove that his way of thinking was right all along. He could also use his knowledge of the Sharingan and Rinnegan to create new challenges for Asura and Indra.
Well, perhaps a plot where Asura and Indra are given a chance to rewrite their history. They start to understand each other's viewpoints better and try to create a new future for the ninja world. They could also meet their descendants, like Naruto and Sasuke, in a different dimension and exchange knowledge and power.
Asura and Indra are important figures in Hindu mythology. Indra is often considered the king of the gods. Asuras were a group of beings. The Asuras were in a constant struggle with the gods led by Indra. They vied for power, control over the cosmos, and resources. There were numerous battles between them. In many stories, the Asuras were seen as more aggressive and power - hungry, while Indra was seen as the defender of the divine order. However, the relationship was complex, and at times, the Asuras also had their own reasons for their actions, not just being pure villains.