Valhalla's Mightiest Warrior

One day Justin woke up in a strange place surrounded by trees and mist where a crow told him that because of his valiant actions in his previous life the Gods of Valhalla had chosen him to be one of the warriors who would fight for them when Ragnarok happened! One problem though... Justin was just an ordinary 17 year old who had done none of the valiant things the crow said he had done... This was gonna be interesting.