So this idea just came to me. Something to drive a couple sessions. A wizard recently introduced a new spell he's dubbed Lunar Incarnation for the battle against lunar monsters. It's in particular important for enchanters, due to lunar creatures' +10 to saves against mind-affecting effects. The Lunar Incarnation spell temporarily alters the target into a lunar creature, giving them all the benefits thereof, while also circumventing the bonus against mind-affecting effects, as long as the caster is the one under the effect of Lunar Incarnation. The spell is gaining some popularity amongst enchanters, but there are rumors that some of them have begun to behave differently. Moreover, clerics find themselves less likely to commune with their gods if Lunar Incarnation is seeing a lot of casting in the vicinity.
The facts: (Feel free to replace your own canon if you like the rumors but not the truth). One of the lunar gods planted the idea of Lunar Incarnation in the mind of its creator. The spell carries a slim chance of warping the caster's mind to better suit lunar purposes. (Will save to avoid alignment change. Most casters have good Will saves). Their real goal, however, is to weaken the hold of the gods of Highpoint. By even temporarily becoming a lunar creature, the caster pushes the gods away. They avoid corruption by unknowingly contaminating their environment on a metaphysical level. So far, the mages are oblivious. As for the creator? He too doesn't know the sinister origins to his spell. He is an unknowing pawn to the lunar gods, who have somehow found sway over him. In truth, a skinstealer possessing a close companion of his has given him a gift that connects him to one of the lunar gods. (Seroficitacit or a new god, as appropriate to your campaign).
I am Omnirahk, half-Rahkshi ("Omni") of the WotC forums. I consider "Psionics in DragonMech" (see my website) my greatest contribution to anything d20 so far. At least, it's my most successful topic.