Well if we're going to have an epic arena we should have guidelines and class's: lvls 1-5 is one arena category levels 6-10 the next. and 11-15 the next. the same matrix would be appropriate to multiclassing (total levels i.e. your 3rd special forces then become enchanted weapon for 2 lvls (so total 5th level). The next comes down to stuff like r.c.c.. With few exceptions you can have 1 r.c.c. (race) though i believe that most r.c.c.'s can be taught different jobs. for example a neo human baby/child/orphan should be able to be trained as something else. (usually at a cost of half thier r.c.c. abilities ((its ofcoarse negotiable.)) my example that i played was a Neo-Human Duelist. (basically a neo-human orphan raised in New Babylon). Really its more thematic then anything. It should make sense that it works like that example, then again good back story can make up for a lot. Should there be other aliens out there that created juicers and the like yes. consider the titan high gravity as an example (though from a g.m. stand point i generally wouldn't allow them to be in anything but the highlevel or unlimited arena...).