One way to develop their characters is through their interactions with other Pokemon. Groudon could have a group of ground - type Pokemon that look up to it, and Kyogre could have a similar following among water - types. Their actions towards these Pokemon can show their protective sides. Also, when they interact with each other, their body language and the way they communicate (even if it's not in words) can reveal a lot about their characters. For example, Groudon might puff out its chest in a show of dominance, while Kyogre might swim in a more elegant and intimidating way.
To develop Groudon's character, you could focus on its fiery nature. Show how it's not just about destruction but also about the renewal of the land. For Kyogre, emphasize its connection to the vastness of the ocean and its role in maintaining the balance of marine life. You could give them internal thoughts, like Groudon might be frustrated with always being seen as the one causing droughts, and Kyogre with being blamed for floods.
For Kyogre, it could be characterized as a powerful but somewhat solitary being. It's protective of the oceans and views any threat to the seas as a direct attack. It's majestic and its movements are fluid like the waves. Groudon, on the other hand, is a force of the land. It's stubborn and proud, believing that the land is the most important part of the world. It's slow to trust but once it does, it's a loyal ally.
In a fanfic, Groudon can be seen as a proud and territorial being. Since it represents the land, it guards its territory fiercely. It has a sense of honor and dignity associated with its role as the keeper of the earth. Kyogre can be characterized as a wise and ancient entity. It has seen the ebb and flow of countless years beneath the ocean waves. It is patient but when provoked, it can call upon the power of the entire ocean to defend itself. They both can be shown as having a mutual respect for each other's power deep down, even though their natures often put them at odds.
One popular 'kyogre x groudon fanfic' is 'The Clash of Titans'. It really delves into the relationship between Kyogre and Groudon in a unique way. The story sets up an interesting scenario where they have to work together despite their natural enmity. It's full of action and also some great character development.
Well, it could be about their eternal struggle in a new light. Maybe in a world where they have to team up against a greater threat. For example, a new powerful Pokemon that is causing chaos in their shared ecosystem. Their powers combined could create a unique dynamic.
The potential for unique relationships. They can be rivals, but also in some fanfics, they become friends or even more. Their relationship can be explored in many different ways, like in some fanfics where they learn to understand each other's importance in the Pokémon ecosystem.
I'm not sure specifically as I haven't read that exact fanfic. But generally, a fanfic about Groudon and Kyogre might explore their relationship in the Pokemon universe. It could be about their battles, their coexistence, or some fictional scenarios where they interact in unique ways.
Sometimes, other Pokémon can be main characters as well. For instance, Pokémon that are associated with water or earth might play important roles. They could be friends or foes of Kyogre and Groudon, depending on the plot. But ultimately, Kyogre and Groudon remain the central focus as their relationship and power dynamics are what the fanfiction is usually about.
To develop Groudon in the fanfiction, you could give it a backstory about how it has always felt alone in its role of protecting the land, which has made it a bit of a loner. When it meets Kyogre, it's full of distrust. But as they are forced to interact more, Groudon starts to see the value in Kyogre's power over the ocean. For Kyogre, it could be developed as a character that has a strong connection to the emotions of the sea. It might initially view Groudon as a threat to the delicate balance of the world. However, through shared experiences, like being trapped in a strange dimension together, Kyogre realizes that Groudon is not just a brute force of the land but has its own kind of wisdom. Other characters in the story, such as mythical Pokemon or powerful trainers, can also play a role in their development. For instance, a mythical Pokemon might give them a task that requires them to work together, and in the process, they grow and change.
You can try looking on fanfic websites like FanFiction.net or Archive of Our Own. They have a large collection of Pokemon - related fanfics, so there's a chance you might find it there.
The theme of redemption can also be present. Maybe one of them has caused some kind of destruction in the past, and through their relationship with the other, they find a way to make amends. It could be Groudon's volcanic eruptions or Kyogre's tsunamis that they need to atone for, and their bond helps them in this journey of redemption.