I like Taleworlds (developer). They released Viking Conquest like a month ago and have a series of great games.

This one is a singleplayer RPG and is quite a refreshing sight. Don't expect a story, do expect an experience in a medieval world, you'll make your story.

Great introduction and if you like it, there's a few expansions to keep you occupied.

Cheers(◕‿◕✿)