Age Of Struggle : Humanities last stand

Humans, Demi-Humans, Beast-Folk, Elves, and Dwarfs have been at war with the United forces of the great demon Lord for over 100 years without a break bringing both sides to utter exhaustion but due to the disunity of the human races the demon Lords army won after using humanities weakness against them. After losing the great war, humanity was forced to pass the impassable Great Stren mountain range resulting in a great loss of souls of the remaining human army and fleeing citizens of fallen kingdoms. Passing through the Great Stren mountains humanity rebuilt what it had lost from scratch, brick by brick, stone by stone. After many years of reorganisation, regret and sorrow, the leaders of each race got together to create a monarchy supported by a council made up of the leaders of each race to make sure the actions, reforms, and laws of the monarch were not biased to a single race, as well as being advisors to the monarch. It's been months since the council formed, and they still couldn't decide. Then suddenly a baby cry was heard outside the tent, halting all arguments on deciding who should be the new monarch. He was a young half elf half human who was bearly a few months old. Almost without resistance, the leaders agreed to make him the new monarch of the federation All leaders agreed to make the newborn child full monarch at the age of 50, before that the child would learn new things from each race, language and culture each year in a different place to learn different ways cultures adapted to the new lands But eventually, all that's good must come to an end. Year 53 A report comes from the Northwind pass stating reports of enemy troops moving into the area preparing for a siege. Peace has come to an end. The age of struggle for survival has begun. Will humanity prevail or will they fall below the knee of the demon Lord's grand army?