The Borellian Nomen are humans who are part of a warrior tribe. Unlike typical humans that form the Twelve Colonies, they have a bony ridge on their foreheads and are from Borella which they describe as "the land of the mega sun and the endless sands." They dislike associating themselves with the Colonials, but there is at least one ship in the Fleet that is apparently controlled by Nomen (The Man with Nine Lives). Despite their dislike for Colonials, they dislike the Cylons more, as they are machines (Baltar's Escape). The nomen believe that they will be the only people to survive the escape from the Colonies.
Much about Nomen is not known, other than the fact that they follow a doctrine referred to as "The Code" and use laser bola as a form of weapon, which they draw with purpose (The Man with Nine Lives). Nomen are also capable of stopping, or at the very least lowering, their life-function for a temporary period of time and have extremely well-tuned reflexes and seemingly super-human strength (Baltar's Escape). They pursue a form of vendetta against enemies, called the blood hunt.
- Maga: Are we not humans? Are we not members of this Fleet with equal rights and privileges? (The Man With Nine Lives)
- According to Encyclopedia Galactica (a non-canonical piece of merchandise published in 1979):
- The Borellians (misspelled as "Borallians") are described as a "fierce, nomadic people whose cruel tribal customs have survived into the Interstellar Age". What is known of them to the rest of humanity is "limited to their military customs", as the Nomen have no clear distinctions between "wars, feuds and criminal punishments".
- Nomen have social organization based on kinship, thus making feuds into wars.
- As to contact with non-Nomen: any crimes committed by outsiders result in the blood hunt, consisting of a group of Borallian Warriors that swear to pursue the criminal wherever they may go. As stated, "Death is the only sanction meted out by blood-hunting parties." The "Borallian Wars" are said to be direct extensions of blood hunts, making the criminal the enemy of the entire people. Both types of hunts may lead in Borallian Warriors dying for the fulfillment of their oaths.
- The Borallian Warrior's ethic was centered around a long knife; this knife meant certain death for outsiders who seen one unsheathed, since a Nomen would prefer suicide to seeing the knife sheathed unbloodied. This tradition, which "stems from a respect for naked violence and a belief that it is not to be employed or threatened lightly", made way to the laser bola (erroneously referred to as the "Laser-Bolt").