im asking about what would need to learn to do stuff like character creation and swapping pieces of armor
Modeling, just need to learn how to make one really, to point you towards a good tutorial to create a character/model from a drawing:
https://www.youtube.com/watch?v=0QT1GNMevfc follow that series of tutorials and you can make one all on your own.

swapping pieces aint so hard either, you could do that with logic bricks in blender or with python.
look at the signature of our moderator Monster, he got a guide/tutorial for exactly that.