The pictures say it all…..Well, either way I would go with Alduin. He can shoot flames and ice, which would make quick work out of Smaug. If it came down to a physical fight, Alduin would have the edge due to his sheer ferocity. I do have to say that his design is a lot cooler than Smaug’s, but I don’t take that into account in the fight. Both of these are powerful dragons, but I would say that Alduin is in a league of his own. Alduin wins.