I'm not ruling out that it can simply be a 'character'. Even then, I'm not sure how well they would get along with everyday business seeing as these things are public information. We have to consider the kind of society this Enlil System has created, and how a person's class can also be a window to their personality. 

Imagine going to a job interview and the boss checking your info and seeing that you are the bloodthirsty 'Cleaver' class. 

"Yeah, you know, it's just... something I do..." 

Then again, monster hunting is always a way to go. But we see no indication of that. And what do her parents/guardians think of their innocent little daughter creating such a class? I just don't know. 

And I suppose not everyone HAS to engage in ranked fights. Based on the information that we have been provided, I assumed they are highly regulated and that only the most qualified high-ranked fighters will be representing the country when it comes to more politically important affairs. Since these have replaced any other form of grand negotiation, and large-scale warfare is considered obsolete. I just can't see normal people being desperate enough to vote for a crazed blood-giddy fighter as their 'national hero'. But then again, I don't know just what kind of rulings and rights are earned through these international duels. Maybe it really is that desperate? 

Maybe losing means so much more.