The Moon

After Renée left Charlie, he met Selene. Selene, who everyone had believed to have faded, met Charlie the night she wanted to see what became of the world she loved. She wanted to make this man happy, as he had made her within the days they spent together. So, when she told him she was expecting, she also revealed who she was. Charlie was surprisingly calm about it, reassuring her that he would raise their daughter to the best of his abilities.
Charlie named her Addison Serena Swan. True to her name, she was a peaceful baby. She would bring happiness to the lonely man, only having a fit when Bella mistreated her. As to keep his daughters from tearing each other apart, Charlie would have Billy Black watch over Addison. Being the goddaughter of the Chief, the council granted her membership into the Tribe. She grew up with the stories, Sam Uley being the older, overprotective sibling she needed. At Camp Half-Blood she met Percy Jackson.
Percy, who just so happened to be the nephew of her father, was like an older brother to Percy. Although Sam was overprotective, it was nothing compared to Percy. Percy would worry about her constantly, refusing to leave her alone unless he knew it was safe. At first, Zeus thought Lady Artemis had broken her oath. They had a trail, even going as far as bringing Charlie to testify. During the Trial, Selene came and explained everything.
After the war against Kronos was over, Percy and Addison defeated him by handing Luke the dagger, they thought they would live in peace and mourn the dead. However, that didn't happen as they were thrown into another war. Selene sent Addison a dream, telling her to go to California.
Lupa had met Addison, greeted her as a fellow wolf, having smelt the La Push pack on her. She introduced some of the werewolf legacies, the ones of her old pack that became more human. She explained that moonstones kept them alive and allowed them to shift into their true forms.