I've ran across time and time again sources claiming Sophie Eriksdotter Lövenbalk, great granddaughter of King Christoffer II of Denmark to be Klaus's mother and Lydeke Diekn / Djäkn as father but as of yet no concrete evidence has been found. If anyone wants a challenge to verify this you're welcome to try as if verified would open up new roads...
Sophie Eriksdotter Djäkn, De Kyren