Ok who would win between Marth and the Black Knight (Ike's arch enemy)!!
Marth: Prince before the time of Ike who fought for his kingdom all alone (at the beginning) and safed it.
He is depicted as a heroic prince, sixteen years of age who was forced to flee his home kingdom of Altea after it was attacked. He then assumes the role of hero leading a rebellion to regain control of his kingdom and save his sister Ellis.

Black Knight: The Mad king's most trusted general! No one knows who he truly is. He killed Ike Father. Uses a big ass sword named Alondite. And he comes back in FE : Radiant Dawn after everybody thought that he was dead! And he has his own music in the battles (it's also on brawl in the castle stage)

Here he is in action