There is more than one artist with this name:
1) Mortuus is a black metal band with a slower paced style using heavy guitars echoing from beyond the grave, deep vocals praising death and occult lyrics that gives a dark and gloomy sensation of rot and decay.
The band was formed in Umeå, Sweden in 2003 by the current band members J. Kvarnbrink (aka Tehôm)(bass/guitars/vocals) and M. Hinze (drums).
Tehôm is currently active in Ofermod where he plays bass and has previously played with Dödfödd(Stillborn) and Shade of Black as a guitarist and as a vocalist in Shade of Black. M. Hinze is active in Ondskapt as a drummer and used to play in Shade of Black as a drummer, bassist and as a backup vocalist.
2) Mortuus is a Deathcore band from Indiana, USA. They released their EP "More Gore than Before" in 2007. Line Up: Joe - Vocals, Nathan - Guitar, Joey - Guitar, Mikey - Bass, Tommy - Drums
Mortuus had disbanded with members going on to form Dissever The Tyrant. Mortuus are now back together as a band.
3) Mortuus (1992 - 1996) is a grindcore band from Serbia, they've released only one album "Educationaly Motivating Electric Shock"