An Angels Demon|| Supernatural Fanfic

When Castiel looses all connection with his angelic powers, he is rescued by the black beast of the night, a wolf. Castiel learns this wolf is not all as it seems, and they form a unlikely bond. But as Castiel returns to the Winchesters, the brothers become suspicious of the blind demon that is always by Castiel's side as it never leaves his sight by day, but by night, is no where to be seen. Who is this angel's unlikely companion? Read to find out.