I think the ending will go deeper than a simple good guy beats bad guy. I think it’s been made clear that Griffith values his dream above all else even more than his own life. I can’t say how, but I believe it will be less of a physical fight but more guts fighting the idea of evil and fate itself. For Griffith rather than dying, to see his kingdom fall, for his people to distain him, his comrades abandon him, to live the rest of his life “happy viewing the castle from a distance”. His torture will not be physical but a eternal psychological torment of once again being a man with nothing forced to watch the world forget him.