Summary: AU PJO & HP Crossover and with multiple OC. Being both a magical and a demigod is supposed to be impossible, but the impossible becomes possible in both mythology and magic. Seraphina Black is a person that is living proof that it is possible as she is a witch and a powerful daughter of Neptune. As wars rage in both worlds, she is forced to make decisions that no one should make, and that change both the mythological world and the magical one. Rated M for language and slight abuse.

Prologue

A/N: I know, starting with a authors note, but this needs to be said. I do not own PJO or HP, I am not Rick Riordan or J.K. Rowling, if I was, things would be a lot different. Also, I want to thank any readers that actually are interested, this has been playing out in my head for a long time, and I'm finally typing it. I hope you enjoy it, and thanks again for choosing to read something wrote from a nobody.

*Neptune's POV*

London, June 25, 1945

"This isn't going to work out, Amelia. It isn't safe for you or for Mia." I say pleadingly to Amelia.

"It will work out Neptune, the war is going to end soon, I know it." Amelia Taylor responded, not worried in the slightest, gazing at the six-month-old child in her arms.

"I'm not worried about the war, I'm worried about the monsters and my brothers." I say quietly, and for the first time, she looks up from Mia.

"You think they are going to try to take her away from us?" She said in a whisper, hugging Mia closer. I don't respond, instead choosing to embrace both of them. The woman I love, and my beautiful daughter.

TIME SKIP

Olympus, September 20, 1945

It has been a few months since I last saw Amelia and Mia, the war has finally ended, and Jupiter, Pluto and I swore an oath on the River Styx to not sire anymore demigods. I must warn Amelia to go into hiding, or to the sea, where I can protect her and Mia.

England

I get there to see the house in smoldering ruins and hear thunder rumbling angrily in the clouds. "Jupiter." I growled. I search the ruins for Amelia and Mia, trying to have hope that they are still alive. After a few minutes of searching, I see an arm, more precisely, Amelia's arm sticking through some rubble. I start crying, moving the wood on top of her body with ease, I roll her over and there is little Mia, her body limp, but she is only unconscious, Amelia saved her from death. I pick her up, and heal her the best I could, and put drachmas in Amelia's hand for Charun. I close Amelia's eyes and travel away with Mia, to a place where she can be safe.

Lotus Hotel & Casino

I walk into the hotel, holding Mia, and go to the front desk.

"L-Lord Neptune." The woman at the desk stammered, I ignored it and put Mia gently on the desk.

"Take her and keep her safe, I will collect her when the time is right." I travel to my palace in Atlantis, steeling my nerves and stopping my tears, everything would be worse if my wife found out. Even the Lotus Eaters would not be able to keep Mia safe if that happens.

And done! Hope you enjoyed (and that it isn't horrible) and more (actual) chapters will be out.