Noxius

The Noxii were condemned criminals taken from their prison cells to the arena, Typically two noxii fought each other, but only one would be armed with a dagger. Having slain his opponent the winner would then be forced to hand his dagger to the next man who entered the arena. If he refused, swordsmen would kill him immediately. The fight would then continue. Other noxii were tied to posts and had wild animals set upon them.