CountryHumans: Demon Slayer AU

When Poland comes back to his village after a long day of work, he finds out that his friend Germany is not feeling well. Determined to help him, he travels long roads to find a cure for him. In the journey, he finds out that man-eating creatures called Demons were real- and his friend was turned into one by the Demon King! Poland must learn to master Sun breathing- a breathing style from Poland's ancestors- before the Demon King can learn how to walk in the sun and become unstoppable.