The peasant revolt at the heart of the default Noble quest, implemented in dNetHack, Slash'EM Extended, and SlashTHEM, is led by the Rebel Ringleader and three other unique monsters: the adventuring wizard, the militant cleric, and the half-elf ranger.
Note that Fighter/Ranger/Cleric/Wizard is a common configuration for the stereotypical four-person D&D party.
"A powerful warrior with a silver sword."
The Rebel Ringleader is the true quest nemesis, as it is she who carries the quest artifact (the Mantle of Heaven or Vestment of Hell) and the Bell of Opening, and it is her death that produces the "nemesis death" message. Be warned, however, that the other unique monsters will teleport to and pick up the Bell and the Quest artifact if given the chance.
"A man of magic. At his word the elements rise up and energy rains down; but as any true mage knows, sleep will kill you faster than flames!"
"A holy man. He can heal his friends and set the sky on fire."
"A woman of nature. She fights with arrows of the moon's metal."
Her arrows may be especially dangerous to a vampiric Noble.
Reference: Chris' Noble Patch