Not many people heard of In Extremo, a German folk-metal band. Actually I wouldn't either if not for the #Gothic game. Then I started listening to them and I fell in love with their music! They did an amazing job, with for example Herr Mannelig taht is a Swedish ballad from the 19th century. Even the lyrics are comprehensible :).
https://www.youtube.com/watch?v=bkX1iNUq6Jw