Holy 7 - sounds fun.
"Hey, you undead, my god is sooo cool, you need to have a divine rank yourself to worship him. Have a banish." *swoosh*
You could think of this god as AO from D&D or as Azathoth from the Cthulhu.
What I think the reason is, that usually pretenders do not get holy magic is, that a unit needs to be sacret for this and then the blessing is in fact based on your own power.