Pyresburg, jewel of the Grand Reman League, is a city renowned for many things. It's arena is not one of them. A dilapidated ruin, it hasn't seen use in over a century. Yet the populace still have the bloodlust of the old Reman Empire. So how do they get their fix of stylized public violence? Two different groups, near antitheses of each other...
The Barfighters' League.
The rich folk of Pyresburg have a strange relationship with the poor. On the one hand, they hold themselves aloof, but on the other, they find many of their "quaint" traditions fascinating. Combine this with dilettantish boredom and a surfeit of money to gamble and the end result is nobles ensconced in private booths of seedy bars, watching professional barfighters duke it out, and gambling on the outcome. The fights are staged, but for all that various crime bosses try to rig them, the fighters are usually too drunk, stupid, or dedicated to their violent art to be relied upon to follow orders in the heat of a brawl. They will, however, usually follow the rules: no weapons (except for bar fittings), no spells, no bothering the rich folk.
The Duellists' Association
Conversely, the poor are always interested in how the high-flyers act. Even how they fight. Many nobles train as swordsmen, and will challenge each other to public duels over the most minor slight. These duels are almost never (intentionally) to the death, and are mostly about showing off and gaining the adulation of the crowd. Official Association Rulekeepers watch such fights and will declare a winner on points, based on style, technique, flourishes and sportsmanship.
Members of both groups despise the other, although their fighting styles share a great deal of theatricality. Adventurers could combine them to great effect in combat, although they would be jeered at mercilessly by any "pure" fighter