Kingmaker Option - Witch Posession

[D-Dubb000]

Hello, fellow gamers. I'm running Kingmaker and one of my players has decided to play a witch with a strong attuning to the "elements," he even has it listed as his character's religion.
So, my question to you is this "would it be delightfully wicked of me to tweak his character just a bit to where his attuning to the "elements" was more of an attuning to the fey elements, namely Narissa? I guess this would play out as Narissa being her unknown, malevolent patron and when the realization of who the character's patron is, the character must choose to betray her teammates or forsake her patron. What do y'all think?
Let me know what you think in the comments and you can check out this witch character at my Kingmaker Obsidian Portal page. http://www.obsidianportal.com/campaigns/65009/characters/iolana

[D-Dubb000]

Also, please offer me ideas as to how to play this out and make it work during the game and mechanics.

[Rickmeister]

I wouldn't have Nyrissa herself be the patron, but simple some kind of other fey. Maybe a sprite that can change into a raven or something?

I did it with my witch, as they received slight bits of information about fey-ness, but always at a cost :)

[D-Dubb000]

Excellent idea. Thanks for the input!