For Percy, his character could develop in terms of his loyalty. He has always been loyal to his friends, but now his loyalty is also towards Calypso. This might make him more cautious in his actions as he doesn't want to put her in danger. He could also become more diplomatic as he tries to get the gods on board with their relationship. Calypso would grow to be more confident. With Percy by her side, she feels more secure and starts to assert herself more in the demigod world. She could start to use her beauty and charm in a more positive way, like helping Percy with his diplomatic efforts.
Percy would likely become more mature. He has already been through a lot, but the relationship with Calypso would force him to think about a more permanent future. He might become more patient as well, as Calypso has her own traumas from being alone for so long. Calypso, on the other hand, would become more open. She has been isolated, but with Percy, she starts to trust more and interact with the outside world again. Her powers might also develop in new ways as she has a new purpose in life - to be with Percy and build a future together.
At first, Calypso might be in awe of Percy's new godly form. But soon, they realize that they are equals in many ways. Their relationship develops as they face opposition from some of the other gods. They support each other through difficult times, like when some try to undermine their marriage. Percy, with his courage, and Calypso, with her wisdom, make their relationship strong and they become a power couple in the divine realm.
One possible plot could be that after all his adventures, Percy somehow finds his way back to Calypso's island. They start to reconnect and realize their feelings have deepened over time. Calypso, who has been alone for so long, is hesitant at first but Percy's determination wins her over. They then have to face the challenges of getting the approval of the gods, especially since Percy has a history with some of them. Together, they overcome these obstacles and finally get married in a ceremony attended by their friends from the demigod world and some friendly spirits from Calypso's island.
In some fanfictions, their interactions are filled with a bit of tension. Calypso, having been alone for so long, may be hesitant to fully trust Percy at first. But as he continues to visit her and bring her lemons, she slowly warms up. They start to share stories, with Percy telling her about his adventures at Camp Half - Blood and Calypso sharing her knowledge of the island's secrets. Their relationship builds over time, and the lemons can be seen as a symbol of their growing bond.
Their relationship could develop through shared experiences. For example, they might go on a quest together to find a lost relic. During this quest, they learn more about each other's strengths and weaknesses and grow closer.
For Percy, he could be developed by showing his growth in understanding different magical elements like the significance of lemons in Calypso's world. For example, he starts to learn about the lemon - related magic that Calypso uses and becomes more attuned to her realm.
In many Percy Jackson fanfictions, Calypso is often portrayed as a complex and tragic figure. She's shown as being both alluring and lonely. Her character is usually depicted with her longing for Percy, as in the original books. Some fanfictions might explore her life on the island before Percy arrived, giving more depth to her isolation.
Often, they start with Percy arriving on Calypso's island. Then, they begin to understand each other. For example, in many fanfics, Percy tells Calypso about his adventures, and she shares her loneliness. This mutual understanding forms the basis of their relationship.
The guests could include Percy's closest friends from Camp Half - Blood. Grover would be there, his presence adding a touch of nature and music. Annabeth would be there to support Percy and also to share in the joy. Some of the younger demigods from the camp who look up to Percy might also be invited. As for Calypso's side, the various nymphs on the island would be present. The talking animals and magical creatures that inhabit the island would also be part of the wedding. And perhaps some of the friendly sea - creatures that Percy has befriended over the years would come to the surface to witness the event.
Their relationship could start off rocky as Triton might be jealous of Percy's relationship with Poseidon. But over time, they could come to respect each other's abilities. For example, Percy's courage in battle and Triton's knowledge of the sea's secrets.
His character would become more confident in his artistic abilities. Apollo is the god of many arts, so Percy would likely be exposed to music, poetry, and painting. He might be more flamboyant in his actions and speech, as Apollo has a certain charm. For example, he could start using more flowery language when talking to his friends or enemies.