Destiny of the Dragonborn

Cheryl was a girl who wanted a normal life,a normal family and to be a normal girl.But when one day she gets attacked by heartless,a mysterious dragon like mark appears on her skin and a keyblade chose her to be the wielder.Then she is thrown into the chaos of helping to save the worlds from the darkness and the mission to find out who she is.But what happens when Sora is added to the mix?