He could learn special combat skills. His dad, Poseidon, might teach him unique ways to use water powers in battle, like creating more powerful water whips or shields.
Percy could learn about his family's history and the secrets of the underwater world. Poseidon could share stories of ancient sea battles and the origin of their powers, which would give Percy a deeper understanding of his heritage. For example, he might learn about long - lost sea kingdoms and how their family was involved in them.
Maybe it's a training area on an isolated island. The island could be a place full of challenges, like rocky terrains and hidden caves. Here, Percy could learn both physical combat skills from his dad and also how to use the natural elements of the island, such as using the rocks as weapons or finding shelter in the caves during simulated battles.
There's also 'Poseidon's Promise'. This fanfic delves into how Poseidon made a secret promise to protect Percy in a way that goes beyond the normal godly duties. It has some really cool action scenes where Poseidon uses his powers to fend off threats to Percy. It's a great read for fans who want to see more of Poseidon's protective side.
One possible plotline could be that Percy has to keep his fatherhood a secret to protect his child from the various threats in the demigod world. Maybe he discovers he has a child from an old relationship and has to balance his new role as a dad while still being a hero.
Another theme is the over - protective father. In these fanfictions, Poseidon is extremely protective of Percy. He might go to great lengths to keep Percy out of danger, even if it means going against the other gods. This often leads to some tense moments between Poseidon and the other Olympians, and also shows the depth of his love for Percy.
His dad might be initially shocked but quickly become accepting. After all, he is a god and has seen many strange things. He would probably use his power to make Percy's life easier during the transition, like providing resources or protection.
In some Percy Jackson fanfiction, Piper's dad is often portrayed as a complex figure. He might be shown as a strict but loving father. He could be a source of strength for Piper, especially when she's facing the challenges in the demigod world. His mortal side might be emphasized, making his relationship with Piper a bit of a struggle as she navigates her divine heritage.
One common theme is sacrifice. Percy often has to sacrifice his own time and freedom to take care of the child. Another theme is protection. He has to protect the child from the various threats in the demigod world. And there's also the theme of growth, both for Percy as he matures into a father figure and for the child as they grow up under Percy's care.
Perhaps Percy is a single dad because his partner was lost in a battle against the Titans or some other great evil. In the fanfiction, he could be dealing with the grief of that loss while still being a great father. He might take his child on adventures around the places he used to go as a teen demigod, like the Labyrinth, but this time it's to teach his child about their heritage and how to survive in a world full of mythological threats.
It's important because Percy can learn more about his past. His dad can tell him things that he doesn't know about his family or his powers.
In some fanfictions, Percy might get trained by a skilled archer who takes him under their wing and teaches him step by step.