disclaimer I do not own harry potter or Vampire and the Potters will be Moroi, but they get separated and they know rose and harry are Moroi this is their story. Harry and Rose will have a twin magical bond. They will be wizard and witch to and they wont be horcrux but he will have the other ones.
It was Halloween night James and Lily Potter are getting ready to put down Rosemarie and Harry to sleep. As Lily was walking up stairs they heard a pop. "Lily take the twins and run he's here. "James said. lily ran up the steps to grab the twins. She called the guardians to come help. Voldemort killed James then came up the stairs and killed Lily. He tried to kill the twins but they had a gold shield around them to protect them. The spell rebound and killed Voldemort. Hagrid showed up to get the twins but he forgot to grab Rosemarie. After Hagrid left the guardians came and took Rosemarie to court in Pennsylvania. Hagrid took Harry to his aunt and uncles house and left him and a letter for his aunt.