Lolth

Lolth the Demon Queen of Spiders is a goddess of egotism, preaching that the ultimate power of the self is achieved through the subordination of others, and the drow revere her above all others.
Greater deity. Above kiaransalee by many levels.
https://www.youtube.com/watch?v=gj2pwWZ5jTc

She is the archetypal Matron Mother, reigning supreme over the other gods through trickery, fear, promises of power, or outright domination. Spiders are her sacred animals, for they weave treacherous snares and kill prey larger than themselves with cunning and poison. It was Lolth who convinced the primal elves to take on mortal bodies, and it is she who weaves the soul of each drow and spins the circumstances of their birth, giving strong-willed drow the chance to rise above their station and achieve greatness.

She is a demanding mistress however, and what she demands above all are sacrifices of blood and treasure. However, the Dark Mother is also fickle in her favor and constantly tests her children – in one famous tale, she denies spells to a house’s priestesses just as they commence attacking a rival, purely to see if they still had the strength or will to defeat them. Her mercurial demeanor and incessant demand for tribute may seem at odds, but Lolth is above all a goddess of ambition and selfishness, of chaos and caprice, one who preaches that might makes right and that rules exist only to serve those in power if they exist at all.

While all drow fear losing Lolth’s favor, so too do they know that if they can survive its sudden absence, then they never truly lost it at all. Chaos may be a pit – but true spiders can climb its walls.

Clergy

Priestesses in menzo. Matron mothers heads of houses all have priestesses.

Rebirth

Drow do not experience Remembrance and dwell in darkness during Trance because Lolth reweaves their souls into new bodies upon death. Lolth purportedly does this so that every drow will live in the here-and-now, aware of their own uniqueness and the temporary and precious nature of this life. Incidentally, this existential fear makes drow heavily reliant on Lolth and her priestesses for protection in the treacherous Underdark, which surface elves would argue is the whole point. Legend has it that the drows' final repudiation of Corellon was when they mystically-bound their souls to Lolth in order to have their truly unique rebirth apart from Corellon; when Lolth was cast out by Corellon, they were banished from his presence too, eternally bound to Lolth, their creator and captor. As a result, many drow see no escape. Given what Lolth offers and permits, many do not wish to.

Drow near-death experiences typically involve ringing; this heralds the presence of Kiaransalee, whose spectral form is covered in loose-fitting necklaces, rings, and arm-bands of purest silver. When a drow dies, the Revenancer springs into action, dragging the soul out of its mortal shell piecemeal back to the Demonweb Pits over a period of eight days, while Ghaunadaur feasts upon the soulless body. During this time, the deceased experiences ever-more terrifying visions as Lolth unspools its soul, day-by-day, hour-by-hour, and uses those threads to weave new drow souls.

Within these eight days, spells such as raise dead can be used to abrogate Kiaransalee’s claim to the soul in Lolth’s name. However, returning from death is an ordeal, and whatever part of the soul that Lolth has already unwoven is not reclaimed; the harrowing visions and slow unravelling of the self often result in profound changes to one’s personality. If the deceased is not raised within this time frame, far more powerful magics must be resorted to in order to bring them back. Spells such as resurrection or true resurrection beseech Lolth to reweave the soul of the deceased. Because Lolth knows what lies within the dark hearts of all her children, the drow brought back (inasmuch as they are “brought back”) knows everything it knew in life and retains any and all skills it had at the time of its death, though such individuals are rarely identical to their former selves. Few priestesses will resort to such powerful magic, however, as they require a considerable investment in resources, and the inability to cast spells after a successful resurrection spell would put said priestess at considerable risk of being usurped by a rival.

An afterlife does not exist in drow religion per-se. While a harrowing transitional period does exist as a soul is dragged bit by bit into the Demonweb Pits, it does not remain there for long or in one piece. Punishment or reward in the next life is entirely temporary and limited to the mortal sphere. However, Lolth is a fickle mistress, and while many believe that she can be placated or propitiated to provide a beneficial rebirth, there is no guarantee; the Spider Queen spins as she wills, according to no whim but her own. Because Lolth encourages the pursuit of sensual pleasures, power, and material wealth in this life, whilst simultaneously promising that nothing is guaranteed or carried over into the next one, her followers are fanatical in their devotion.