The Life of a guardian of the forest

There was a man named Michael. He was a teacher he was loved by alot of the students untill the great war happened he had to go fight so his child didn't have to. But he was thought to be dead in the war so he was alone in a forest but there was a portal that lead him into a new world called Valhalla it was a world of vikings and warriors it was a beautiful place but the ppl was wondering how a normal man come to their world but then the portal closed a chief of the village came and said

-nobody has come through that portal for 3000 years. i guess you are the new guardian of the forest. : the man was confused about what has happened to him. and he said

- how did i end up here: the elder explained him the story of the guardian of the forest he said you are supposed to protect the forest from monsters and any other human but i don't know why the portal chose you from the human world?