Unexpectedly Human

Lucy Heartfilia dies after Team Natsu kicks her out of their team and she leaves the guild in a fit of rage and falls of a cliff. Lucy misteriously wakes up in the arms of a dark haired stranger. The stranger hold Lucy hostage for a week and suddenly lets her go. He returns for Lucy and she goes willingly. Who is he and how does he know Lucy? What does he want with her? More importantly what is the evil aura Lucy is picking up on in the presences of this man?