19

The demon army kills off the remaining human army's and route them while letting the ones running escape.

The Humans sign a peace treaty to stop the fighting as the war cost them 490k men while the demons only lost 80k leaving them with 220k this was a heavy blow to the humans and was the most devastating fight.

The demons let them be and sign a truce for 600 years but the humans won't honor it and start to rebuild and ally withy the dwarfs and elf kingdoms to kill the demons.