Here are some places to get free 3D character models. You can edit the meshes to make them medieval.

Turbosquid Do a search for characters and you can select within your price range as well.

Terminal26 has some free low poly but they are not medieval. You can use them as a starting point.

Make Human is a free human character mesh maker but is high poly as well but can be run through a poly reducer. If you wish to use this the polies are in the mouth basically so run it through a polygon reducer and then go through and take out a lot of that mouth detail you do not need. Action3D is an excellent polygon reducer. I am very pleased with the results it gives.

I did a google search for 3D model free human and came up with a lot of resources. Be sure they can import in to MED or Milkshape if you purchase that and are not too high poly if you do not have a good polygon reducer.

Expensive methods

If you can afford it and want some good 3D character models and it is not your strong point you might want to hire that work out.

There is also Face Gen but I would not use it as per the morphing as it is too high poly for A7. I have other plans on how to use it with A7.