Spartacus slaying one of the executioners in the arena.
Execution ad Gladium was a form of punishment enforced in Ancient Rome. The condemned were forced to fight untrained against professional Gladiators until killed in the Arena.
In the series Gods of the Arena, four prisoners are put to death in this manner, including the escaped slave, Diona. Although Diona was not given the privilege of combat, but was instead simply executed by Caburus.
In the series Blood and Sand, the Thracian known as Spartacus is sentenced to death in this manner, but is allowed to live after slaying all his executioners. Spartacus himself is assigned to perform executions later in the season, against a group of random prisoners for the honor of Mercato's grandfather, and later to perform the execution of Marcus Decius Solonius.
In the series Vengeance, Oenomaus, Crixus and Rhaskos were to be executed ad Gladium by a number of gladiators, including Gannicus. Rhaskos was the only one of them to be put to death. Crixus and Oenomaus escaped with the aid of Spartacus during the destruction of the Capua Arena.