In a way i'm surprised this one didn't make it to the game yet: David, the Hebrew warrior King. I think most everyone knows the story of David and Goliath - (give the character a really big sword because later he used Goliath's sword).
David's historicity is no less questionable than many of the other characters in the game who may or may not have actually existed (Ragnar, for example). So in terms of legend and mystique around a warrior, it doesn't get much more legendary than him.
And in terms of popularity, how many movies have there been over the years, children's books, there was even a history channel series recently. He's certainly more ubiquitously known than most of the other legendary warriors in the game. And in terms of lore: giant slayer, killed lions and bears w/ his bare hands, was said to be a match for 1000 men on the battlefield and singlehandedly slew 10's of thousands... his lore is pretty rich.