About Venus Malfoy

What if Lucius had a brother who died and promised to take care of his daughter Venus? Venus Malfoy is Draco Malfoy cousin. She has to live with aunt and uncle what happened when Harry falls for her will she like him back? Will Draco be okay with it?What of Snape had a sister? Who just so happen to be Venus mom? What I'd she isn't in Slytherin? But Gryffindor? And what If Harry never like Cho or even meets her?