Carols and Spies

Carols and Spies is a collection of novellas that take place in the world of The Winter Souls Series by Jennifer Kropf. Complete with six stories of Winter legends, this prequel weaves together the origin tale of the underground cathedral in the Red Kingdom and the spark that brought the Carriers of Truth into existence.
Synopsis for A Blend of Harmonies (Novella, The First) in Carols and Spies:
Red versus Green. It has always been this way since the beginning of the war.
Charlie and Cora are from different kingdoms. Charlie is a son of the woods, the pines, and the deep earth-shaking drums of celebration and war–a true Green Kingdom citizen.
Cora is as Red as its gets; a daughter of crimson dresses and scarlet stained-glass, living among the royals in the Red Kingdom palace with all its luxuries and twisted games. But when they're brought together by a mysterious power who calls himself Elowin for a reason neither can seem to figure out, they learn they each carry a weight on their shoulders placed there by their own kingdoms. And if they want to be free, they'll have to figure out who exactly Elowin is, what he's doing, and why his plan involves them both before Charlie is caught in Red Kingdom territory where he will have to face the wrath of the Red royals.
In Carols and Spies (Collection, The First), meet a keyholding spy, a magic singer, a Prince of the Pines, a pair of elite hunters, an Ink Whipper, a Savior, and a young, wicked witch called Mara Rouge who aims to take them all down.