Sebastian X Reader: You are Grell's Sister

[DISCONTINUED] You have the infamous Grell as your annoying brother. You lived all your life as a reaper with Grell. You were kinda getting bored with that so, Grell offered you to go to a friend of his' house who was in the human world. You see a huge mansion instead, seeing a boy with an eyepatch and a butler who caught your eyes. You have found deep feelings for the butler, Sebastian. Though, Grell has the same feelings. Will Sebastian accept your feelings? What will happen? A sudden plot twist when things get good? Or a beautiful ending on each problem?

[Not my picture for the cover. Credits to original creator]