Well, it'd be a huge deal. First, the gods would probably be really angry at Artemis for breaking her oath. But at the same time, they'd be curious about this new being. The demigods would be divided. Some, like Percy's friends, might be more accepting. They'd try to protect the child from those who would want to harm it because of who its parents are. Others, especially those from more traditionalist camps, would see it as an abomination.
The demigod world would likely be in shock. The hunters of Artemis are sworn to chastity, so for Artemis to have a child would go against everything they stand for. The other demigods might be confused and a bit scared too. Some might see the child as a threat, fearing it could have some sort of super - powerful abilities.
The reaction in the demigod world would be complex. Artemis having a child would disrupt the status quo. The hunters would be in turmoil, some might feel betrayed. Demigods from different cabins would have different views. The children of Athena might study the implications of such an event from a more intellectual perspective. The children of Ares might see it as a sign of weakness in the divine order and want to prove themselves against this new entity. And Percy's friends would be caught in the middle, trying to uphold their loyalty to Percy while also dealing with the shock of this unorthodox situation.
The gods might also get involved. Zeus, for example, would not be happy that a human organization had kidnapped one of his son's (Poseidon's) demigod children. He might send some signs or even directly interfere. Athena would be giving Annabeth advice on how to deal with SHIELD. And Poseidon himself might stir up the seas near SHIELD facilities to show his displeasure.
The existence of Artemis's child would create a lot of chaos in the Percy Jackson world. Firstly, the other goddesses might be jealous or feel that Artemis has broken some unspoken rules. The child could also be a target for various villains in the series. This would force the heroes like Percy and his friends to step in and protect the child. Moreover, the relationship between the different pantheons might be affected. If Artemis is part of the Greek pantheon and her child has some unique powers, other pantheons might see this as an opportunity to gain an advantage over the Greeks.
The balance in nature would be disrupted. Artemis is the goddess of the hunt, the moon, and nature. Her death could cause strange phenomena in the natural world, like animals going wild or the moon's cycle becoming erratic. This would not only affect the demigods but also mortals who depend on the stability of nature.
He may also try to figure out what went wrong. Percy is a smart demigod, and he would likely not just accept the betrayal without trying to understand the cause. So, he might start investigating, talking to other characters who might have some insight, like the other demigods or even some minor gods who are friendly to him.
The child might be extremely powerful. With Percy's demigod abilities related to water and his heroic nature, and Artemis's connection to the moon and her hunting skills, the child could have a blend of these. Maybe it could control water in a way that's related to the moon's phases, like having stronger water powers during a full moon. And it could be an excellent hunter, with a natural affinity for the wilderness.
One common theme is the exploration of the relationship between the male and female demigods. For example, how Percy's more impulsive nature contrasts with Artemis's more reserved and strategic approach. Another theme is the idea of protecting the demigod world. Fanfictions often show Percy and Artemis joining forces to fend off new threats that the original series might not have covered.
She could also be angry. Given her power and status, she might feel slighted by Percy. She may take some form of revenge, not in a malicious way but perhaps by making Percy's life a bit more difficult during his quests. For example, she could send her hunters to interfere or withhold some information that could be useful to him.
The child would likely be brave, like Percy. Percy has shown time and again that he's not afraid to face danger. And from Artemis, the child would inherit independence. So, they would be someone who is not afraid to take on challenges alone. Also, they might have a sense of justice, coming from both parents who have their own moral compasses.
Artemis would be in shock initially. Given her status as a powerful and independent goddess, the idea of being forced into marriage is unthinkable. She would likely try to use her divine powers to break free from the situation. If she can't do it immediately, she might start to negotiate. She could offer other things in exchange for her freedom from this marriage. And if Percy shows any sign of taking advantage of the situation, she would not hesitate to put him in his place.
Percy would probably be really confused at first. I mean, one moment he's a normal demigod and the next he's a jackalope. He'd likely try to figure out what happened and how to change back right away. He might be a bit frustrated with Artemis for doing this to him without much warning.