Good question!
For that particular Titan (Oceanus), he assumes 'ownership' of the city you do not choose between Rome/Pompeii. There will then only be 10 gladiators you will have to face, PLUS the CF Gladiator that you did not draw between Appius/Sextus.
For added challenge, players may add more CF Gladiators (TLC/KS/Special prints/GenCon-themed chips).