Not worshiped actively, Mvoorin Geist is more of a hidden god. Worshiped not by word, but by deed, every murder and every secret hidden is done so in his name, even if in another's service. Unknown when or if this deity was founded, or just came into being. One will never find a temple, shrine or other place of worship, for the Midnight Geist's name is hidden until bestowed upon those who'd best suit this divergent god.
Known to actively initiate it's followers into the destruction or manipulation of lore, to keep records vague, and things ever hidden, for knowledge is power, and mortals are not deserving. Mvoorin Geist has two classes of servants, and perhaps named so similarly as to keep those who wish to pry into his agenda off track. Geist Hounds; large, dark and malevolent beasts, as well as the Hounds of Geist, who are the mortal practitioners of his craft, the arsonists, thieves and manipulators, and traitors to the races of the world.
For one to even gain the eye of Mvoorin one has to be of a particularly malevolent nature themselves. (60+ corruption) For those dark beings The Midnight Geist will bestow upon them three visions. The first, of his dark hounds chasing the recipient through the darkest parts of their minds and cities, through such horrors only their own subconscious could create (1d4 insanity). The second, The hounds hunt other people about them, those the recognize, perhaps from earlier days, or just those on the streets about them. Tearing them apart and devouring them. (1d4 insanity). The last is that, they themselves are of the hounds, moving with the others, sewing discord and stealing the secrets of others, keeping the world dark. (1d4 corruption)
After they have received all three visions, they will get Geist's mark upon their body somewhere, much as if having savaged by a wild animal. Leaving their true nature all but unknown but to others of their kind, and even then, it is difficult to tell, for there is no leader, only a pooling of resources, if that. Should a cult ever be discovered, it is likely to be burned out of society, Mvoorin's last act of self destruction has played it's part, and the cancer of suspicion lies forever within the place of operations heart.