You are Erens little sister, After Eren had brought Mikasa home to live with your family, She took an instant liking to you, you and her became like sisters almost immediately, after the fall of Shiganshina, Mikasa became extremely protective of you so much to the point you were seen almost everywhere with her. And when she saw you talking to someone she disliked she scolded you, and it got to the point where even Eren interfered when you weren’t around but Mikasa got upset and yelled at him.