There's also a chance that it could be a god in disguise. Gods have been known to have relationships with mortals and demigods. So perhaps a god took on a human form and had a relationship with Thalia, resulting in the pregnancy.
Another option is that it could be a character who has been her friend for a long time. Their relationship could have evolved over time and led to this situation. For example, a close friend who has always been by her side and they had a moment of passion that resulted in the pregnancy.
It could be one of her close friends from the guild. Maybe Jellal, considering their complex relationship in the original story. There's already a lot of history between them, and this could be a new development in their relationship.
It could be a long - time boyfriend that we haven't known much about in the original story. Maybe he's a character who was in the background but now becomes central to the plot.
One possible plot could be that Thalia has to deal with the shock of the unexpected pregnancy. She might struggle with how it will affect her life as a demigod. For example, she may worry about how she can continue her duties while being pregnant. Maybe she'll also face judgment from some of her peers in the demigod community. She could then start to think about the future of the baby and whether it will inherit her powers or face the same dangerous world she has.
It could be her existing partner from the original story. For example, if it's a story where she's in a relationship with Edward, then he would be the likely father.
It could be his long - time partner. They might have had a very loving relationship that led to this situation.
Perhaps it's a mysterious stranger she met at a party. They shared a brief moment together, and now she's pregnant. Or it could be an old acquaintance who has always had feelings for her and took advantage of a vulnerable moment.
Maybe it's a new character introduced specifically for the fanfiction. This new character could be from a different faction or group, and their relationship with Makima could be full of intrigue and mystery. The pregnancy could be a result of some sort of strategic alliance or a passionate encounter between them.
It could be one of her close friends in the story. Maybe someone she has had a long - standing relationship with and the pregnancy was an unexpected but not entirely unwelcome result of their relationship.
Another option could be a mysterious figure. For example, a character from another dimension or a new character introduced specifically for this plot twist. This could add an element of mystery and intrigue to the story.