Bijuu Children: Chaotic Maelstrom
There is no greater love than that of a mother for her child. A father's love comes at a very close second. Mix in an obsessive primordial, a deal made, an asshole fox, a not all the way dead mother, and you have the perfect Maelstrom. Or The Shinigami completes her task during the sealing of the Nine-Tailed Fox but...