Mr--Timelord

This is something that I've been thinking about for a while now. Does the WoL have potential to be overcome by Nidhogg and become his thrall from holding the other eye, or does the blessing protect them, if it counts as tempering?

Appreciate the response

For lore purposes, I'm curious. Has the lore mentioned anywhere at all that if someone were to succumb to the Darkside, if there was a cure, or would be able to bring them back to their normal selves?