A number of characters in the series display certain slave brands. Branding was done either through the method of burning the flesh with a branding iron or tattooing of skin with ink.
Mark of the Brotherhood
The Gladiators belonging to Quintus Lentulus Batiatus displayed a "B" shaped brand on their right forearms symboling the House of Batiatus. The brand was a sign that a recruit had passed his final test, officially becoming a gladiator.
Mark of the Domina
While unknown if Thessela, Amana or Gaia's Slave bore this mark, it is known that Lucretia marked her body slaves Melitta and Naevia with a butterfly shaped tattoo. This tattoo symbolised a bond between them, to never be parted.
After Sinuessa fell to Spartacus and his rebels, many escaped slaves from across the Republic traveled to the rebel held city to seek refuge. One of the methods of proving travelers were slaves and not Roman spies was to check for brand or mark upon their entrance through city gate. One such slave was Belesa who when demanded showing of brand by Saxa, exposed her breasts to show she bore the letters "β X" upon her right breast.
Later, when Caesar and his men tried to enter the city he tricked Spartacus into letting him enter by claiming to be a slave whose dominus branded his slaves "close to cock and cunt", and that he had cut his off.
Runaway slaves who were re-captured were often branded Fugitivus, often having the word tattooed to their forheads. One known Fugitivus was Kerza, a runaway later condemned to be one of Batiatus' gladiators. After being captured by Glaber's troops in Vengeance, Aurelia was also branded fugitivus, however the words were instead carved into her forehead.