You're welcome!
Hope you find something to your liking.

Now that we are approaching the end of recommendations that properly fulfill your request, judging by your enjoyment of Overlord you may also find that playing through the campaign of Stronghold. You would have to watch a video of the game being played to see how the peasantry treat the protagonist, a Lord rather than a Knight. "Mornin', your Lordship", "Place your granary, Sire."

Defender of the crown

What about:

Darklands

It doesn't get much more medieval than that and you can play a knight, if you want.