Windaria [Movie]

The mountainous kingdom of Paro and the coastal city-state of Itha had been at peace for over a century. They would have remained that way but for the ambitions of Paro’s power-hungry king. Paro invaded Itha, despite the love between Jill, Paro’s prince, and Ahanas, Itha’s princess. Caught between duty and emotion, the star-crossed lovers were forced to fight a war to its bitter conclusion. Isu was a simple farmer from the neutral village of Saki, but he saved Itha from being destroyed by a spy from Paro, and found himself hungering for wealth and glory that the Ithan monarchy could provide. Agents from Paro made him an offer to fulfill his wishes, and he left his wife Marin behind in what would turn into a battlefield between the two kingdoms.
Basically think: a better version of Romeo & Juliet combined with a better version of The Oddesy