Bonded By the Sea (A PJO fan fiction)

Kaia, a mysterious newcomer to Camp Half-Blood, arrives severely injured after being ambushed by monsters while searching for the camp. Barely surviving the attack, she is rescued by a group of demigods and wakes in the infirmary to discover she may be the daughter of Poseidon, making her Percy Jackson's sister. Overwhelmed by her newfound heritage and connection to the sea, Kaia struggles to process the revelations and adjust to her new life among demigods.

Her divine lineage is confirmed when Poseidon publicly claims her, marking her with a glowing trident and solidifying her place as a child of the Big Three. While grappling with her identity, Kaia begins to feel a sense of belonging at camp but quickly learns she is a target for monsters and rival forces.

Kaia's life takes another turn when Chiron tasks her, Percy, and Annabeth with a dangerous quest. The trio must retrieve a powerful artifact stolen from Olympus, a mission that tests their bravery, teamwork, and Kaia's fledgling abilities. As they face deadly challenges, Kaia learns to harness her connection to the ocean and finds strength in the bonds of friendship and family, ultimately stepping into her role as a child of the sea god.

This takes place after the battle of Manhattan.

I do not own any characters except for Kaia. All the other characters belong to the amazing Rick Riordan.