Underground ghouls

From The Vault

The underground ghouls were a loose organization of disgruntled but peaceful ghouls in Necropolis, forced by Set to live in the city's sewers, presumably due to their unwillingness to partake in his hostile administration of the City of the Dead. They were apparently unarmed and form no threat to anyone, but were one of the most helpful factions in Necropolis, telling the Vault Dweller where to find the water chip but requesting him to fix the pump first.