We've been told a few times about how Commoner was supposedly a much stronger warrior that led to him getting acknowledged and knighted by his feudal masters, but I don't remember actually ever seeing him in action. Somehow, it's Slave who's always stealing the spotlight when it comes to fighting in this story.
Now would've been a nice time to show his combat ability off if it wasn't for the fact that he's inconveniently injured and maybe even more helpless than she is...