Magnetius was Titus'Champion, proclaimed by him to be one of the finest ever to come from his ludus. Magnetius' weapon of choice seems to be a single Gladius Hispaniensis, an older and longer type of Roman sword not traditionally used by gladiators. Magnetius wields the weapon two handed with deadly purpose and strikes with such force that his opponents often lose balance and even control over their own shields.
Adrianus was a tall, lean man who wielded an axe in battle (marking him as a "Starz-style" Secutor, presumably). His name suggests he is Roman. When the episode he appeared in was first broadcast, fans speculated that Adrianus was actually the prequel Doctore, as his face is not seen and lanista have tendency to use their former top gladiators as trainers. This was proven false by the Blu-ray release of Gods of the Arena, where the prequel doctore was revealed to be named Ulpius.
Acerbitas fought with a sword and shield. He bore a faintly Greek appearance, due to his white beard and the shape of his helmet, and his name would suggest this origin too. His fighting technique, great strength and prowess as a Champion could also suggest Spartan heritage.
Dolor was a fierce Champion who fought with a hammer. His name, and the fact that a hammer was his weapon of choice, give strong indication that he might be Illyrian of birth, his name hailing from one of his nation's southern tribes (in modern day Albania).
Zephyros was a large titan of a gladiator who fought with a single sword. Similar to Gannicus, he wore a plumed helmet (which possibly denoted his elevated position of Champion amongst his fellow gladiators). His name marks him as presumably of Greek origin.