There's a chance that it's a legendary Pokemon other than Arceus. This Pokemon has a special connection to Arceus and senses the creation of the new dimension. It then decides to explore it first, maybe to see if it poses any threat or opportunity for the Pokemon world as a whole.
I think it would be a young and adventurous trainer. Someone who is always looking for new challenges and isn't afraid to go off the beaten path. They might be led there by a strange Pokemon that they've never seen before.
The new dimension might be a place where time moves differently. For example, a day in our world could be a year in that dimension. This would affect how Pokemon grow and evolve there. There could also be new types of Pokemon abilities that are unique to this dimension, like the ability to manipulate the very fabric of the dimension itself.
The character development of Arceus as a female can be really engaging. It could explore how she interacts with other Pokemon or trainers in a different way compared to the traditional male Arceus. Also, the 'lemon' part might involve exploring relationships and emotions that are not typically shown in the main Pokemon series. This can add depth and a new layer of storytelling. For example, it could show a more complex relationship between Arceus and a trainer that goes beyond the usual catching and battling.
Fanfiction about Giratina and Arceus can take many forms. Some may focus on epic battles between them, imagining different scenarios where their powers clash. Others might delve into their creation myths and how they are connected in the fan - created universe. For example, a story could explore how Giratina's banishment to the Distortion World by Arceus affected its personality and its view of the other Pokemon and the world itself.
Obviously, Arceus itself is a must - include. It's the god - like Pokemon in this universe. Also, characters like Volo can add a lot of depth. His complex motives in the game can be further explored in fanfiction, perhaps he could have an even more convoluted plan involving Arceus in a fan - created story.
Redemption is another common theme. Giratina, being banished, could be on a path of redemption in some fanfictions. It might try to prove itself to Arceus or the other Pokemon. This can lead to really interesting character development stories.
One difference could be the focus on Arceus. Since Arceus is such a powerful and unique Pokemon in the lore, 'pokemon arceus lemon fanfic' might explore different power dynamics and relationships compared to fanfics centered around other Pokemon. Also, the 'lemon' aspect, if it implies a more mature or romantic theme, could be unique in how it's applied to Arceus compared to other Pokemon.
I'm not sure specifically which ones are the most popular. However, usually, the ones that gain popularity are those that have a really engaging plot. For example, a story where Arceus has to save the Pokémon world in a unique way. Also, if the lemon aspect is tastefully done and adds depth to the relationships in the story, it might attract more readers.
The theme of mystery is quite prevalent. Both Arceus and Giratina are shrouded in mystery in the Pokemon lore. Fanfictions often expand on this, creating stories where trainers or other Pokemon are trying to uncover the secrets behind these two legendaries. For example, stories might revolve around the origin of Giratina's exile and Arceus' true intentions for the Pokemon world. There are also themes of friendship and cooperation, where unlikely allies come together in the presence of these two powerful Pokemon.
Team Rocket might be main characters as well. They could be constantly trying to capture Ash or his Pokemon because of his special status. Their bumbling attempts to take advantage of Ash's link to Arceus could add a lot of comical and action - filled moments to the fanfiction. And of course, Arceus itself could be a major character, guiding Ash in some way or interacting with him directly.
It's unique because it challenges the traditional narrative of Ash's journey. Instead of just aiming for badges and winning Pokemon Leagues, he now has the most powerful Pokemon. This could lead to him having a more global impact on the Pokemon world. Also, the relationship between Ash and Arceus is likely to be very different from his relationships with his other Pokemon. Since Arceus is so powerful and has a god - like status, their bond might be more of a partnership to achieve greater good rather than the typical trainer - Pokemon relationship.