Demonic Sponsors (悪魔の保証人, Akuma no hoshounin)? are important concepts in Shin Megami Tensei III: Nocturne, important deities summoned to the Vortex World and key to the successful completion of a Conception.
Shin Megami Tensei III: Nocturne
A significant aspect of Nocturne's story is the creation of a new world from the Vortex World. Part of this process includes a human survivor of the Conception accumulating enough Magatsuhi to summon a Demonic Sponsor: a powerful being who supports a human's Reason and lends him or her power in creating the new world. The three Sponsors presented in Nocturne are:
Doubtlessly there are countless other possible Reasons and Sponsors.
Yuko Takao also tried to gain a demonic sponsor in the form of Aradia, not knowing that Aradia itself was not truly considered a viable god due to her existence being forbidden in the Vortex World. However, it is mentioned that such "shadow gods" from the Shadow Vortex do try to get involved in Creation in order to become real deities.
The Manikins also attempted to create a new world, but having lost their seer and spiritual leader Futomimi and his powers of prediction, and lacking either a coherent Reason (only wishing for a world of absolute equality, with no masters or servants, but with no clear indication of how to create it) or a Sponsor, their cause was hopeless.