Board Thread:The Last Sovereign Discussion/@comment-27713488-20170707041037/@comment-10672901-20170818222605

To those wondering how Wendis could be Ivala/the Mysterious Divine Being and not know about it, LoZ:Skyward Sword does something like that with the goddess Hylia, and a similar logic could be applied here. As for how the faithful could still hear Ivala's voice while Wendis was alive, she could have been an offshoot seperate from her main being, a la Flemeth's amulet from Dragon age 2.

"Must I be in only one place?  Bodies are such limiting things.  I am but a fragment cast adrift from the whole.  A bit of flotsam to cling to in the storm."

If Wendis is actually the MDB (whom I'm assuming is Ivala, based off of the sparse context clues) this would explain so many things. She knew she was about to be trapped/captured, so in order to prevent all of her power and influence from being nullified/stolen she cast off a piece of herself in the form of a mortal, with no memory of who/what she truly was. This suppression of Wendis' divine nature would essentially be a more extreme version of what Simon himself does to hide the fact that he's a shard bearer from the other Incubus Kings. When Wendis died the MDB would have not only regained the (relatively small) amount of power that she had previously cast off, but also unintentionally absorbed Wendis' memories and emotions, which would explain the parting comment from Mithyn about her putting her faith in "that meaningless man" (by which I and others assume she's referring to Simon).