Celeste is the sister and guardian of Aphrodite.

Spoiler

While fighting against some devils with Angels Lily, Daisy and Salvia, she was knocked down to earth. She lost her memory during the fall. She begins to use the name Sakura. On earth she fell in love with Hanasaki Shouichirou, a young photographer. They had a child together, named Momoko. Three years later, Limone finds Celeste and restores her memory. Celeste says goodbye to her family and leaves. Before she leaves she gives Momoko her ring, which is part of Something Old. (Description Credit: Wikipedia)