Chiron could play a significant role. He has a wealth of knowledge and experience, and could offer advice on both the pregnancy itself and the potential future of the child. Thalia could also be a great supporting character. She and Annabeth have a long - standing friendship, and Thalia's tough - love attitude could be just what Annabeth needs sometimes, especially when she's feeling down or worried about the pregnancy.
Tyrion Lannister could be a great supporting character. His intelligence and political acumen could be useful in protecting Daenerys during her pregnancy. He might also offer some witty remarks and advice regarding the situation. Another could be Missandei, as she is Daenerys' loyal handmaiden. She could provide emotional support and help with practical matters, like preparing for the baby.
The main characters are most likely Annabeth and Percy. Since Annabeth is the one who is pregnant, she would be a central figure. And Percy, being her partner, would play a crucial role in protecting her and the unborn child in Tartarus.
There could be some original characters created specifically for the fanfic. For example, a healer or a midwife type of character who helps Clara during her pregnancy. And then there are the allies they might have made in their previous adventures. These characters could come to their aid when they face difficulties related to the pregnancy, whether it's protecting them from enemies or just helping with day - to - day tasks.
Leafpool could be a main supporting character. As Squirrelflight's sister, she could offer her medical knowledge and emotional support during the pregnancy. Bramblestar would also be important. As Squirrelflight's mate, he could be there to protect her and help with preparing for the kits.
Melissa's sister could be a great supporting character. She could offer advice based on her own experiences with pregnancy and motherhood. Maybe she helps Melissa with baby shopping and gives her tips on dealing with morning sickness.
The other gods would have mixed reactions. Some might be amused or see it as an opportunity to gain an advantage. For example, Hera, Zeus's wife, would be extremely angry and might seek revenge on Annabeth. The other demigods would be divided. Some might pity Annabeth, while others might see her as having overstepped or being too ambitious. The child, if it was born, would be a source of both hope and fear for different characters. It could be seen as a powerful ally or a dangerous threat depending on who you ask.
One great fanfic could be 'The New Chapter of Percy and Annabeth' where it beautifully depicts their married life and the anticipation of their baby. It shows how Percy is overprotective and Annabeth is handling the pregnancy with her usual strength.
The fanfic could also take a more complex turn. Annabeth gets pregnant at a time when there are threats to the world. She has to deal with the fact that she's bringing a new life into a potentially dangerous situation. There could be a prophecy related to her unborn child, which adds more drama. Her pregnancy might also be a sign of hope for the future of their world, as the child could be a great hero in the making.
Most likely, Percy could be the father. They have a strong relationship in the original series, so it would be a natural choice. Their chemistry and shared adventures could be the basis for a story where they start a family together.
Another possibility is that it could be a god in disguise. Given the complex relationships between demigods and gods in the Percy Jackson universe, a god could have fallen in love with Annabeth and fathered her child. This would bring all sorts of divine drama and complications to the fanfic.