PJO-percy's secret sibbling?

You were Percy Jackson's sister, you were slightly younger than him. The odd thing was that you were a demigod, but not of Poseidon. Unclaimed. This was extremely uncommon, but it sometimes happened.
You weren't a half blood? Well you were, not of Poseidon. That's what confused you the most, Poseidon left before Percy was ever born, let alone to have another kid.*

Percy dragged you into camp and was rambling about everything
"oh, I'm sure you'll love sparring, and oh! you know there's this lava wall you can climb and-" then his smile faded... his friends, the heroes of olympus looked mad, and confused.. he never told them about you.. his sibbling.. they got deffensive
annabeth:"Percy who is this new kid?" kinda jealous
Leo: "ohhh hoho! did you have an affair on new york or who's this beauty" joking, even tho he still looked suspiscious of you
Jason:"Percy? who did you bring here?" suspiscious of you and slightly mad
Piper:"oh sweetie, what's your name and who are you?" trying to use charmspeak
hazel:"Perseus.. who's this..?" she was slightly afraid
Frank:"uhhh.. like, really, who's that?" protective of hazel
Nico:"oh, great... a new kid.. and related to percy.. just awesome.." sarcastical and grabbing the hilt of his sword for precaution
percy tried to defend you and explain but all his friends were already being rude to you.

they're in the percy jackson universe.