I don't know who knows them but I didn't see a thread for them, so:

Gernotshagen are a pagan/viking/black metal band from Germany, formed in 1999. They have released 2 full length albums to date, as well as a demo and a couple dvds. I'd strongly recommend their 2007 album Märe aus Wäldernen Hallen.

http://www.myspace.com/gernotshagen

Also, I should note that the Metal Archives label them as folk rather than viking. I usually trust their definitions, but imo they got this one wrong.