There are three artists with this name: 1.) Hierophant is very slow, raw and atmospheric funeral doom metal project of Xathagorra Mlandroth - one of the founders of funeral doom itself (with Thergothon, Skepticism, Funeral and others).
The music is always very slow, depressive and weighty (extremely). All tracks are quite primitive, but it can be requited by unique and deep atmosphere of solitude and endless darkness.
Continued by Catacombs.

Read more about Hierophant on Last.fm.