The other gods who oppose the union of a mortal (or demigod in Percy's case) and a goddess could be antagonists. They might see the baby as an abomination or a threat to the order of the divine world. For example, some of the more traditional and strict gods could try to harm the baby or separate Percy and Hestia.
There could be dark forces or monsters that sense the power of the new - born baby. These entities might want to capture the baby and use its power for their own evil purposes. They could be ancient monsters that have been lurking in the shadows, waiting for an opportunity like this to strike.
Even some jealous demigods could be antagonists. They might be envious of the special powers the baby is likely to have. They could try to undermine Percy and Hestia's parenting or even try to turn the baby against its parents by spreading false rumors or causing trouble in their lives.
Perhaps some rogue demigods who have turned against the gods and don't believe in Hestia's values. They could be jealous of Percy being chosen as her champion. They might try to undermine his efforts and steal any power or artifacts related to Hestia that Percy is protecting. They could form a sort of anti - Hestia group, causing trouble for Percy at every turn.
Maybe the plot focuses on how Percy and Hestia adjust to being parents. Percy, who is used to his own adventures, now has to think about the safety and upbringing of a child. Hestia, on the other hand, has to deal with the new dynamic of having a half - mortal baby. They might face challenges from the other gods who are not happy about this union and the existence of the baby.
Perhaps a story where Percy is chosen by the Fates to mediate between Hestia and Artemis. There has been some sort of misunderstanding between the two goddesses. Percy, with his charm and unique perspective, tries to get them to see eye to eye. He arranges meetings in different places - sometimes in Hestia's warm and cozy domain, and other times in Artemis's wild and untamed forests. Through Percy's efforts, they not only resolve their differences but also realize that they can work together for the greater good.
One way their romance could be portrayed in fanfiction is through Percy seeking solace in Hestia's hearth. Hestia, being the goddess of the hearth, represents warmth and home. Percy, having gone through so many harrowing adventures, might find a sense of peace with her. They could share quiet moments by the fire, with Hestia listening to Percy's tales of his quests. Their relationship could be a slow - burn one, starting from Percy's initial respect for her domain and growing into a deep, unspoken affection as he realizes how much her presence means to him in a chaotic world of gods and monsters.
In Percy Jackson fanfiction, a relationship between Percy and Hestia could be really interesting. Hestia is the goddess of the hearth, representing home and warmth. A love story might involve Percy finding a new kind of peace and comfort in Hestia's presence. Maybe after all his adventures, he discovers a different kind of love with her, one that's more about stability and a sense of belonging.
In a Percy Jackson and Hestia lemon fanfiction, it could be that Hestia uses her powers related to the hearth to create a lemon - like glow around Percy. This glow gives him an extra boost of energy during a battle. They form an unlikely bond, with Hestia seeing Percy as a symbol of hope for the future of the demigod world. And the lemon aspect could be metaphorical, like a fresh start or a new hope that Percy brings, much like the refreshing feeling of a lemon.
There's also 'Hestia's Protege'. In this fanfic, Percy becomes an unofficial protege of Hestia. It has some really interesting plot twists. For example, Percy learns some ancient secrets from Hestia that help him in his battles against the new threats emerging in the world of the gods.
Hestia's possessiveness can shape the plot in many ways. It might lead to Percy being isolated from other characters who could be important to his development. This in turn can create a series of events where Percy has to either break free or come to terms with Hestia's possessive nature. Also, it could attract the attention of other powerful beings who either oppose or support Hestia's possessiveness, adding more twists to the plot.
The Titans could be antagonists. Even though they have been defeated before, some of them might hold a grudge against Percy and Annabeth and see their baby as a new target for revenge. They could try to kidnap the baby to use it as a bargaining chip or to corrupt it to their side.
It could be that the author of the fanfiction wanted to create a unique dynamic. Perhaps Percy's character in this fanfic has different values and goals that conflict with Hestia's, so he hates her.