Board Thread:Spoilers/@comment-75.84.100.56-20130202200725

Sorano is a sister to a celestial mage. She is a kind and warm person. She was captured by Zeref. Yukino often has bad (luck)

She is Lucy.

Lucy is a celestial mage. (convenient how they also together have all the zodiac keys). Lucy's personality, though vague matches Sorano's description. Future Lucy seemed to have a presence similar to Zeref. Lucy's name comes from a guild called Lucky that was missing a K.

As for her parents and upbringing we have no clue as to if shes adopted, rescsued from Zeref or is actually blood related. 