It's from unarmed in McMMO. You can read more about it here. The higher your level gets, the more damage you do with your fist with the damage being capped at 9.
Also swords are the actual worst form of weapon in Mcmmo Minecraft. You're better off with Axes, fists, or bows to do anything unless you're looking for aoe attacks.
That's true and you can even deal AoE damage with the Axes right click ability so it's pretty pointless to have a sword unless you really want to attack faster than the axe.
