There are multiple artists with this name:
1) Nerthus is Folk/Black Metal band from Austria formed in 1999 by 3 members: Alex Hiebaum (instruments), Clemens Hiebaum (keyboard) and Daniel Geiger (vocals). On their second album called "Scattered To The Four Wainds" Mirko B. came to the horde. After recording third album "Black Medieval Art" Daniel quit from the band.
Nerthus has 4 full-length albums:
Escape from Suction - 2000
Scattered To The Four Wainds - 2002
Black Medieval Art - 2004
The Crowned's Reunion - 2007