Boutoku no Naruto has Kyuubi willing to help Naruto out of hatred for the shinigami. When Naruto learned Edo Tensai instead of Kage Bunshin, Kyuubi offered him a deal.
Kyuubi: "Because I hate. There are many things I hate. The Sage of the Six Paths. Madara Uchiha. Hashirama Senju. Mito Uzumaki. Minato Namikaze. The toads. Kushina Uzumaki. But more than anything else, I hate the Shinigami. He stole over two thirds of my power, and claimed the Namikize's soul in return, a violation of his own laws and rights. The Shiki Fuin, the contract with the Shinigami, works on a simple basis. A soul for a soul. He did not take my soul, merely my power. When I was sealed, he had nothing to do with it. By the ancient laws, he should have let the Namikaze go, or at least send him to the Pure World, and return my power to me. But he didn't, breaking ancient law. ... You see, he has stolen from me, so I will ensure that he suffers for it! You Naruto, are the key of my vengeance. Through you I will make him suffer. All I ask is that you call back many, many souls, I don't even care for what, and in return, I will give you what all other jinchuuriki can only dream of, my full support."