Roman gladiator dub-con! Except not really!
Eh, it read like a bad contemp romance with some historical garnish tossed over it. Worst waste of resource ever. Why go to all the trouble of setting up such a specific period and then abandon it for some weird alt-reality setting that barely uses any of the rules/culture/structure of the time?
The protagonists hardly appear to live in the society they're in; there's some attempt to try and build this around the eponymous gladiator master's free spirited approach to life, but even that gets terribly confused when the authors also try and make him your average wealthy, ambitious Roman jockeying for power.
Some of the historical stuff was kind of neat but that did not fill the gap, just to be clear. Hot strigil scraping scenes can only carry the fantasy so far.
The characters were terrible
. One's a broody Mcbrooder intent on REVENGE, and the other's a shining beacon of reason and emotional truth that will make Mcbroody see that LOVE CONQUERS ALL. As master/slave dynamics go, it's more deeply unsatisfying than I can express. As storylines go, it's so old and done to death I don't know why you'd bother.
The sex is repetitive and tedious. Caelius turns into a panto character every time he gets his toga off, if panto characters ever stepped over that line. Gaidres gets a bit of mileage out of being allowed to top, but that's used one too many times as a narrative tool to help us understand how spesh Caelius is.
Second star is for the depth of research. Not recommended in any other way.