Ayashi no ceres
Ayashi no ceres is my all time favorite anime series. The english adapted form of the series is known as Ceres: celestial legend (art and story by the creator of Fushigi Yugi, Yu Watase).
It's about a 16-yr-old grl name aya mikage who leads a fairly normal life, but all this changes the day the moon and 16 stars aline (her 16th b-day) and her destiny will overtake her. On her 16th b-day she heads to her grandfather's house with her twin bro, Aki mikage. At the house her whole family is waiting with sad faces....later on in the story her family tries to kill her! her dad dies for her! And she finds out that she can transform into an ancient and very powerful tennyo or a heavenly maiden (celestial maiden) named Ceres...but Ceres is furious and out for revenge...