There are 13 according to Wikipedia, which would be about normal for a cable series.
I have to warn you, it has moments that feel a little Xena Warrior Princess, and not just because Xena is IN IT.. just some of the actors, obviously chosen for their muscular physique and not for their acting chops, are a little crappy. Like they went to that beach in California they always show on TV (can't remember the name of ti) and just picked out some muscled men to play gladiators. Fortunately those guys aren't the main stars of the show, I guess they probably had a hard time finding real actors who are that beefed up. They do lots of hilarious face acting! lol.. it's not supposed to be hilarious. (haha.. just found out one of the terrible actors, Manu Bennett, was actually on Xena!).
It does have the kinda awesome Peter Mensah as the scary gladiator trainer cracking the whip, plus John Hannah trying to disguise his Scottish accent (still heard them rrrrrrr's). ALSO an elf plays a bad guy! Craig Parker!