actually, in Shinto, you can become gods, there is actually one god in Shinto (i forgot which ones, there are a lot of gods in Shinto) that used to be a scholar, when he died, the emperor decides to make him the god of education, since he's the personification of God (if you want to be specific, the emperor is a demigod) on Earth, so it is very possible that these 3 brave soldiers would be make into gods, which one, i do not know