One of many bands headed by prominent Swedish prog-metal figure Dan Swanö, Pan.Thy.Monium stands out as one of his more unusual musical projects. Essentially a progressive death metal band, PTM's three albums supposedly tell the story of Raagoonshinnaah (the god of darkness) and his battle with Amaraah (the god of light), but the vocals (provided by Robert Karlsson, Swanö's future replacement in Edge of Sanity) are totally indecipherable and generally considered to be nothing more than random death metal growling. The group's music is highly unusual, encorporating confusingly dense structures and instruments like keyboards and even saxophones into their experimental death metal style. At the time of their debut album in 1992 their identities were unknown, going instead under aliases. The project was ended by Swanö in 1996, though there has been some degree of interest from the other members in resuming it without him.

Source : http://www.progarchives.com/artist.asp?id=2328