Slave-Gladiator in the Dune CCG
Feyd-Rautha fighting a slave gladiator in the 2000 miniseries
Gladiators usually were members of the Slave-class of the Faufreluches, trained to fight in the planetary Arenas for entertainment of the Nobility and the crowds. These Gladiators were often drawn from prisoners of war and usually drugged by means of Elacca, especially when set up against free Arena-fighters.
After the subjugation of Arrakis by the Harkonnens, Atreides warriors re-entered into the arena for the entertainment of the nobility. A fight featuring Feyd-Rautha describes a meeting with an Atreides soldier who had carved the Eagle of Atreides into his flesh and his subsequent death when Feyd cheats by using a code word to paralyze the soldier and by having poison on the black blade, rather than the white one.