Lolth - The Queen of Spiders

The Underdark is ran by Drow who worship the demon lord Lolth as a deity. Lolth enacts her will through communicating with the top tier Drow houses. These top houses then disseminate her will to the rest of the Underdark. Lolth's will is unchallenged and followed without question by the dark elves.
The only threat to Lolth's power is her rival Arnon - The Queen of Decay or Lady of Rot. The Mushroom Queen desires to rule the Underdark by usurping Lolth, though she is regularly outmatched due to Lolth's drow army.