Lucyandzerefsiblings Histoires

Lucy is the sister of Zeref. Zeref can kill people by accident if too many people were around him but Lucy is the only one who can be near him. Lucy can heal and has mastered all kinds of magic. He only visits Lucy two days every two months...what happens when the guild meets him for the first time? What if she has another brother? I DONT OWN FAIRYTALE!! HIRO MASHIMA DOES!!