Alastor's Sibling || Alastor x Sibling!Reader

turns out that alastor has a sibling

their name is Y/n

But here's the thing what I'd they are here for the extermination. What If their on the inside what I'd their the strongest angel in heaven like how alastors is the strongest demon. Their title (self given of course) The radio angel

Y/n was the total opposite of alastor. They were an the best kid, but still loved their brother, alastor (idk his human name tbh if you do PLZ TELL ME) more than their mother.

Their mother always loved Alastor more than him, but alastor loved Y/n.

Idk who made the book cover tbh