What is necroism?

Answer 1

Necroism is a primary belief that life in this universe is a mistake which must be corrected. They believe that the original religious beliefs were soaked in blood. This revelation was brought about by the discovery of the Underverse, which is described as another universe in which life is cherished and even the dead are brought back to life. The Underverse is both the afterlife of the Necromongers and the ultimate destination of their interstellar journey. Entrance to the Underverse is restricted to those who follow the Necromonger religion. There also seems to be a concept of each person having an appointed time of death in their cosmology ("due time"), and if a person is killed before his due time (the criteria for this is never explicitly given) he will not pass on to the Underverse. The Lord Marshall has seen the Underverse, and his extraordinary abilities are derived from this. Seeing the Underverse is not a requirement to being Lord Marshal, however, as most of the Lord Marshals never saw it before ascending to the throne. Instead, Lord Marshals tend to be appointed either through succession or assassination (as in the case of Riddick) as per the Necromonger law that dictates "you keep what you kill." Information from the DVD extras say that the first act of a Lord Marshal is to make a pilgrimage to the gates of the Underverse.

Answer 2

Necroism is the practice of venerating or worshipping the dead. It could involve rituals, beliefs, or customs centered around death and the deceased.