OUAT x DEATHLESS crossover for desperateploy
In which one Evil Queen and Dark One find out they are but small fish that have wandered out of their pond and into the wide ocean. Marya and Koschei have more on their hands than a dispute between a miffed queen and a cursed princess. There is a war between Koschei and his brother, Viy. So vast that it has leaked over even into this alternate world, and the war is going badly.
[A bout of brainstorming led the both of us to the realization that OUAT is endless in crossover possibilities, feeding her love for the damned things. Marya and Koschei are from the Russian fairytale of Koschei the Deathless, and the wonderful novel named Deathless.]