Maybe the plot would revolve around the relationship between Percy and the goddess. It could show how they met, fell in love, and decided to have a child. Then it might explore how the other gods and goddesses react to this union and the birth of the child.
The fanfiction could be about the child's journey. As the child grows up, they discover their own identity and powers. They might face enemies who are threatened by their existence, being a product of Percy and a goddess. Percy would then have to protect the child and guide them on their path to self - discovery.
It could be Aphrodite. Given her domain of love, it would be an interesting take. Percy might be charmed by her beauty and grace, and they could end up having a child. The child might inherit Aphrodite's charm and Percy's courage.
One possibility could be that Percy has been leading a double life. Maybe he had a relationship in the past that he kept hidden, and now the existence of the child is coming to light. The story could explore how he copes with this new reality and how it affects his relationships with his friends and family.
Perhaps the story could focus on Percy's child trying to live a normal life in the mortal world but constantly being drawn back to the world of the demigods. They could struggle with fitting in at school while also having to deal with strange occurrences that only they seem to notice, like seeing mythical creatures in the corner of their eye. This internal conflict between two worlds could drive the plot forward.
It could be Annabeth, who was made a goddess in some interpretations. Their kids would be really smart and brave, inheriting Percy's heroism and Annabeth's wisdom.
In the 'percy marries a goddess fanfiction', perhaps it starts with Percy accidentally stumbling into the goddess's domain. She is initially cold towards him but as they spend time together, she realizes his good heart. Percy, on the other hand, is in awe of her beauty and power. Their relationship develops slowly, facing opposition from other gods and goddesses who think it's not proper. But they overcome all the odds and marry. Their marriage could then be a symbol of a new era of cooperation between mortals and immortals in the fanfiction world.
Well, in a Fem Percy becomes a goddess fanfiction, perhaps the story begins with Percy being in a life - threatening situation. Instead of dying, some ancient magic or a divine intervention transforms her into a goddess. As a goddess, she might have to deal with the politics of the godly realm. For example, there could be gods who don't want a new goddess to disrupt the existing power balance, so they try to undermine her at every turn. And Percy, being Percy, would fight back and try to find her place among the gods.
Perhaps the story is centered around a mystery that only Percy and the curvy goddess can solve. The goddess might have some special powers that Percy needs to utilize in order to overcome the obstacles. They could also develop an unlikely friendship or even more as they work together.
Well, one possibility could be that Percy has been on some sort of adventure and during that time, he discovers a child in need. He decides to take the child under his wing and brings the child back to his world. Then, he has to deal with the reactions of his friends and family, who are both surprised and a bit worried about this new addition.
Maybe it could be a new character. A mysterious woman who Percy meets during one of his adventures. This would add an element of mystery to the story.
It could be Aphrodite. Since she is the goddess of love, it would be an interesting twist. Percy might initially resist her charm but eventually be won over by her true self. Their marriage could bring a new understanding of love to the world of the fanfiction.