My sister is a Doppelganger and I am a Valkyrie

Elena Has a twin sister. They both have brown hair and are tall and thin. But on the night of their parent's accident, Gyda Gilbert was saved by fate instead of a Vampire. "You will live because of the Gods. Others are dying when they should not, so you will live when you should not." now she must discover her role as a Valkyrie and what that means for her and her friends and fam.