Nukoku's behavior here reminds me of one of Incubus' addicts begging him for more, more.
If Nukoku doesn't have Incubus/Maya's entire key, she might have been at least given a fragment of it and sent out to do Incubus' will.
I wonder if Incubus had a plan for taking on Gog, and if he did, would infiltrating her from the inside with the devouring hot black flame be it?