Nachtmahr

There are atleast three bands using the name 'Nachtmahr'.

1) Nachtmahr is the solo project of Thomas Rainer (Better known for his other projects: L'Âme Immortelle and the now defunct Siechtum)...
The debut album, "Kunst Ist Krieg" (Art Is War) is a brutal mix of dirty hard techno and power noise with elements of industrial.

2) Nachtmahr is a German black metal band from Thomas Helm and Ulf Schawdorf of Empyrium. Nachtmahr is an old german synonym for 'nightmare'. The actual year of creation is unsure, since Helm once claimed that the idea for this project reaches back to the mid-90s.

3) Another German black metal band from Günzburg. they have released two split ep's so far. the first ep with sun of sleepless was released in 2004 at the lupus lounge label. the split ep with helrunar was released in 2005 also at the label lupus lounge. there was only "trollzauber" on it.
the style is a concentration of intense, dramatic atmosphere, magical-moody Black Metal, complemented by two apparently contrasting voices and dramatic keyboards.