"...what is the lowest command general you have ever won a battle with?"

Well, for me it would be a 0 star general since I never had any commander with negative levels in MTW.
It all probably boils down to my rather Spartan approach to these things I guess - I kind of expect my
pixel-generals to be fit for command. If they are not, they don't command....

As simple as that really.
I like to give everyone a chance. Besides, I didn't realize this guy was a negative general until later (I know, I know). But I was surprised as he still can win battles, just not as easily as your many starred hunks.

Now I had another interesting thing happen. The horde attacked Poland (remember that door I opened?), but with only archers and cav. I had a mixed group up on a decent sized hill. I had two xbow cav unit. I eventually rout the horde, with even their cav leaving (not routed). So I had earlier killed some artillery units as well as a few archer units. I saw the archer units going, some fleeing, some moving away. I attacked, and killed quite a few of them, but after one cav unit hit the 4th unit, already routed, it routed my cav unit! Hard to figure, a routing unit routing an enemy!