Personally, I bring to Blood Gods all gladiators which I find interesting, one way or another. How competitive he or she will be in this environment depends on many things - your own build, your strategy, the opponents builds and strategies, the types of gladiators in the bracket, the opponents which you get to fight, luck and so on. The builds in Blood Gods aren't very dynamic though, so the bracket visibly changes its composition every 6-7 months on the average. If your aim is a competitive gladiator, go with some of the tested builds (read the Blood Gods fights for some time to get an idea how they work), otherwise just do what will be fun for you.