The following religions exist in Menzoberranzan, though most are hidden. With each is listed cleric (sub-)classes allowed by the religion, but that does not mean PCs will necessarily have the chance to be a member of the religion’s clergy.
Abbathor: The dwarven god of greed is also the most frequently followed deity by duergar but few of his clergy operate in the city (in this respect Laduguer’s are more plentiful). Almost all trading caravans, even slave trading caravans that include clergy of Ladaguer, include or are headed by Abbathoran. Lloth’s priestesses endure their presence just as they do those of Ladaguer’s faithful, though Abbathoran that are not of grey dwarven stock find that they must leave the city as soon as their business is finished (and they must finish it quickly) in order to survive and remain free. Dwarven clerics and specialty priests serve Abbathor. His clergy are all male.
Ghaunadaur: It is ironic that this amorphous god’s faith is even more of a threat than Vhaeraun’s and yet is less noticed by Lloth’s followers. This is because Ghaunadaur’s faith also appeals to non-drow while Vhaeraun still holds the drow race supreme. Ghaunadaur has a number of hidden faithful and even a few clergy in the city and nearby in the underdark. This faith may be growing. Ghaunadaur has clerics, specialty priests, shamans, and witchdoctors.
Kiaransalee: Kiaransalee’s faith is present in the city though it is carefully buried (no pun intended). The revenancer’s clergy work slowly and carefully, hoping one day to gain revenge for their current oppression. Occasionally one or a few of Lloth’s clergy mysteriously turn up dead or disappear altogether. Even when found dead, they cannot be questioned. Kiaransalee has both specialty priests and clerics, though she favors specialty priests and cleric/magic-users the most.
Ladaguer: The dwarven taskmaster god (Ladaguer is not a god of magic and magical items, instead he is god of toil, labor, and hard work) is an excellent god of slavery and so is accepted in the city by Lloth’s clergy as long as there are no open ceremonies or attempts to spread the faith openly (even just among duergar). Ladaguer’s priests have accepted these restrictions (and spread the faith slowly, carefully, and secretly, or at least privately) and so continue to prosper, even if their numbers grow only slightly. Ladaguer is served by dwarven clerics and specialty priests. His clergy are all male.
Lloth: Though the name is perverted from the more usual Lolth, the Demon Queen of Spiders’ religion is dominant in the city. To openly proclaim another religion (or even just follow another) is to invite swift death. This is especially true regarding rival powers that drow might end up worshiping. Lloth is served by clerics, specialty priests, and witches. She only allows males to be clerics (and that rarely) and they can only rise as high as 4th level in most cases.
Menzoberra: Menzoberra was the drow priestess of Lloth who led the drow that now live in Menzoberranzan and Ched Nasad from a war torn drow city long ago. Since her death she has become a minor demi-goddess revered in both Menzoberranzan and Ched Nasad as a servant of Lloth and a goddess of new settlements, travel, wanderers, survival, and patron (under Lloth, of course) of both cities. Menzoberra has only clerics and a few witches among her clergy and only commoners worship her (no cleric of Menzoberra can be a noble, regardless of skill). She accepts both male and female clergy, with the same restrictions as Lloth herself (males cannot rise above 4th level except with exceptional service or abilities). Generally her worship has remained outside the city, as her clergy are hired by those wishing to establish a dwelling in the mantle or dark dominion. Her followers also make a living as guides and many hunters follow her. With the rise of trade, however, her prominence has grown, and many caravans and merchant houses include her followers now for their knowledge of survival in the wild underdark. As well, it is generally seen to be safer for a drow male to have one of her clergy around than one of Lloth’s and many merchant companies are led by males (while they may possess magical power, clerical healing is a necessity for those who’d travel the underdark).
Orcus: Orcus is undoubtedly not the only demon lord besides Lloth with power in the city but his is probably greatest. Orcus is not interested in converting the populace and battling Lloth, however, instead he quietly accepts clerics, specialty priests, and death masters into his service, most of which leave the city when they are powerful enough. He is not too particular about race but his followers in the city only recruit those of ability, thus leaving out kobolds, goblins, and others that hold no interest for them. Orcus is presumed to be growing power here in a trickle and sending it out to overwhelm the scattered forces of Kiaransalee, one of his enemies. Some of Lloth’s priestesses even ignore non-drow worshipers of Orcus as long as they don’t try to convert drow, seeing this as a way to battle the spread of more hostile religions. Orcus also allows shamans and witchdoctors and some have been encountered in the underdark in the past.
Selvetarm: A few clergy of this servant god of Lloth’s have been secretly brought to Menzoberranzan by some of the noble houses. House Baenre has openly brought some and is trying to convince the council to allow Selvetarm’s faith to be carefully spread in order to counteract the spread of Vhaeraun’s faith in the city. For now, political rivalry as well as a very real fear of weakening the power of Lloth’s priesthood has prevented the open establishment of the new religion, though all the matron mothers of the city’s noble houses have been alerted to the presence of Selvetarm’s clergy in House Baenre. Selvetarm is served by clerics and specialty priests, of which a specialty priest and a cleric/fighter have been brought into House Baenre (and may even be training more already…).
Slave Racial Gods: The racial deities of the various races employed as slaves in the city are stamped out as best possible by Lloth’s clergy. This has been almost completely successful, especially among the slaves themselves, though occasionally new slaves turn out to be clergy of one deity or another. These make excellent sacrifices to Lloth. There are always rumors in the slums of certain racial deities, particularly of gods of secrecy, having followings and clergy in the city, however.
Unusual Gods: In a city that does so much trade, it’s inevitable that other, unexpected deities will find toeholds. Other demonic powers may have a few worshipers in the city and occasionally a clergy member or two, and certain other evil powers have visiting clergy from time to time (most notably Loviatar, Kanchelsis, Mellifleur, Squerrik, Great Mother, Gzemnid, Ilsensine, Maanzecorian, and Merrshaulk) that are tolerated or not based on the precepts of the church and activities of the clergy. Shar, Ilbrandul, and Moander have all found ways to establish small cells of their religions in the city. While Moander corrupts and Shar converts, Ilbrandul offers the safety of the open underdark to the oppressed. While currently weak and scattered, this religion is the one most directed toward a general slave revolt, a revolt, that if properly supported by Ilbrandul’s clergy, could do serious damage and even allow many slaves to escape. But for now, this is a long way off.
Vhaeraun: Vhaeraun’s faithful keep working to subvert Lloth’s faithful and to attract males to his service. The priesthood of Lloth in the city is well aware of their efforts and is constantly vigilant against them. Unfortunately, any non-noble priestess that has not passed the Test (which occurs at 6th or 7th level) and any non-priestess of Lloth of any sort is not revealed the secret of Vhaeraun’s faith and his incursions so it is even harder to fight. Vhaeraun is only interested in drow worshippers, however, so his faith has not caught on among those who are truly the least fortunate. He is served by clerics, specialty priests, and witches.