Marth and Fox are very different in their method of attack and both arguably have the edge over the other. Marth would quickly overwhelm Fox in a close combat battle while Fox would have the edge at a distance. If Marth had a little more speed, then he may have won this battle. As it stands, I think that Fox’s long range abilities provide him with a decisive advantage which will grant him the win. Marth isn’t Zero and he cant hope to reflect the blows forever. Fox wins.

Update 2/7/2019 Thanks to Fire Emblem Warriors Marth is strong and fast enough to win this round. Marth wins.