We'll Be Okay (слэш)

Orochimaru didn't expect he'd ever raise a child. Now, stuck with the child of his dead lover, Kakashi, he must learn about being a parent.
Kakashi never wanted his father to die. He never expected he'd someday have to live without his father. But Orochimaru was an okay substitute. Maybe.
Or a series of one shots in a fix it universe where Orochimaru took Kakashi in after his father died.