Theres a sci fi book, trilogy even i think, and i was wondering if someone

[perpetualnothing]

could help remember what its called? Ok, i remember reading these books, they were sci fi, there were no humans, it was all aliens, There were different races, i believe there were 3 main races, but i could be wrong, i only actually remember 2, one was a reptilian type race, they were the ones who controlled everything, they were the royalty and what not. I remember the picture of one on the cover, and they had a frill like those little lizards have on earth. Then there was another race that was mammalian, basically a big furry alien, something like a wookie. They were enslaved by the lizard race, and the main character was one of these. I think female maybe. I remember she fought in a gladiator type thing.