Raksha and Holy Charms
According to the core Exalted Second Edition book, Holy Charms have special effects upon creatures of darkness. That book lists various creatures of darkness, including"unshaped Fair Folk" but makes no mention of shaped Fair Folk.
Later text does not necessarily support this wording. In reference to creatures of darkness, page 209 of the Manual of Exalted Power: Lunars says "treat him as a creature of darkness, just as the Fair Folk." Technically, it doesn't carefully specify whether that is: unshaped only, shaped only, or all the Fair Folk.
The newest Scroll of Errata for Exalted, the 160 page one declares:
"The Unconquered Sun did not bother denouncing the gnats that swarmed at Creation’s edge in the Time of Glory, reserving his rancor for the vast and terrible things that lurched through the primal depths of the Wyld and occasionally sought to snatch his chariot from the sky as it rose or set. As such, shaped raksha are not considered creatures of darkness for the purpose of Holy Charms, but unshaped raksha and their Emanations are."
I don't know how much sense this really makes, given that Fair Folk are much more dangerous than the game's zombies are. If the Unconquered Sun has historically reconsidered what qualifies as a threat, as a list expanded beyond "vast and terrible things that lurched" suggests, then it would seem like the things that nearly wiped out Creation might stand at least on the level of the walking dead who hadn't really threatened it until about 4 or 5 years ago when the Mask of Winters chose to show his power to the world. If he hasn't reconsidered the list, then how did the dead get onto the list?
Some of this seems like an evolution of the game setting. In 1st edition, I feel that it wasn't particularly clear exactly why a creature was affected by Holy attacks. Demons and the undead seemed pretty natural answers to those of us who played Dungeons and Dragons when we were kids. Fair Folk didn't seem to fit the bill. However, we eventually decided that the keyword Holy is literally controlled by the declarations of the Unconquered Sun (and certain Solars tapping into his power) as to what qualifies as a "creature of darkness" and what does not. All evidence suggests that this decision is made according to his ruling of whether something is an enemy of Creation, which is supported by his motivation. As such, the mass invasion of Creation by Fair Folk, which resulted in chaos in heaven, gods without domains, and nearly completed the Great Contagion's attempt to destroy all life, seems like the sort of incident which might have gotten the Unconquered Sun to make a quick declaration, even if he wasn't moved to directly join the war on the ground.
Of course I don't even buy the errata argument, in the first place. It seems to me that even before the Primordial War, the Fair Folk would have been one of the clear enemies of Creation. The Primordials built Creation as a fortress against the Wyld, after all.
There are also other considerations. It seems to me that Fair Folk being subject to Holy Charms makes the Lunars and the Dragon-Blooded cooler. Their stand, particularly that of the Lunars, against the Balorian Crusade is made easier to understand if there were Lunars armed with Holy Charms involved.
I can see one negative here, and that is the issue with a potentially ever-growing list of "creatures of darkness" which leaves few antagonists in the world of Exalted which are not subject to Holy attacks. I am not convinced that shaped Fair Folk are worthy of exclusion from such a list, however.
I did come up with one possible approach which I think could be more nuanced than the Unconquered Sun being incapable of determining the difference between Fair Folk threats and walking dead threats. It occurred to me that perhaps Ignis Divine did declare Fair Folk to be enemies of Creation, but was convinced to pardon them from that status as part of whatever mass oaths the Eclipse Caste managed to arrange with Fair Folk during the First Age. I'm not really happy with that solution, but it feels better than gimping the Unconquered Sun's tactical analysis ability to this degree.