Percy Jackson Grandson of Voldemort

So Percy meets Dumbledore asking for him to come to Hogwarts saying he has magical abilities. Percy doesn't want to go, but Hecate tells him to. I will Make Dumbledore, Snape, Sirius and Fred alive.
Snape, Hermione, Luna, Neville, the Weasley twins, Sirius and Draco are demigods. Harry and Ron won't like him. After BoO and in the Order of the Phoenix