The Free City of Harat in my Barbarian Conqueror King has been taken over by a slave rebellion 20 or so years ago, which was led by gladiators (particularly of the Lizardman kind). Now this city is pretty anarchic, and the gladiators’ culture dominates - strength, bravado and fighting prowess are celebrated. Instead of the slave gladiators of the old regime, however, now arena fights are usually done by willing participants. This includes professional gladiators, warriors trying to prove themselves, and duellers who solve their differences by the sword while the crowd watches. Criminals may also elect to have trial by combat (typically against dinosaurs or other criminals) in lieu of other forms of punishment (if they survive, they are free to go - they have bought their freedom in blood).

There are generally three types of matches in Harat:

Show games, which inflict non-lethal damage, and are usually done until one combatant surrenders, or falls unconscious.

Blood sports, in which lethal damage is used, but are usually won once one combatant shed significant blood (i.e. is reduced to half or less of his or her HP).

Fights to the death, with no rules.

Fighting is typically done at the Harat arena, or in local inns, with the audience placing bets on the combatants. The more lethal the fight is, the higher the bets. The winning gladiator gets a portion of the bet money.

What I’d like to have help with is how much money can a gladiator earn by fighting in the arena? And how much can a character earn by betting on fights?

A gladiator died in only 10% of the matches; most were fought to wounding or standstill

Earnings for a gladiator were 3x the earnings of a normal citizen; earnings for a star gladiator were 12x the earnings of a normal citizen or more

Earnings were paid per bout; top fighters could earn enough from one bout to buy their own slaves (1500 denari/slave) and estates

Translated to ACKS:

An average urban-dweller earns 12gp per month or 144gp per year. Therefore a normal gladiator would earn (144x3) 432gp per year. Assuming 4 bouts per year, that is 108gp per bout.

A top gladiator might earn (144x12) 1,728gp per year. Assuming 4 bouts per year, that is 432gp per bout.

1 denari ~ 1 sp, so 1500 denari = 150gp. This suggests that our price range is roughly correct for per bout winnings; a top gladiator could buy 3 slaves.

This would suggest that a typical gladiator is around a 1st or 2nd level fighter, while a champion gladiator is 4th level (“hero”). Occasional superstars would ascend to more glorious levels.

If an entry-level gladiator fights 5 bouts per year and earns 100gp per bout, plus 15xp for the win, and a 5% bonus from STR (120xp total), he’ll advance to 2nd level after 16 bouts, about 3 years.

Assume he’s now earning 200gp per bout, plus 15xp for each win and 5% from STR (225xp/bout) he’ll need 9 more bouts to reach 3rd level. That’ll take 2 more years.

He’s now earning 400gp per bout, plus 30xp for each win (tougher foes) and 5% from STR (450xp/bout), he’ll need 9 more bouts to reach 4th level, or 2 more years.

Assuming he started at age 18, he’s now 25 years old and a hero of the arena.

As far as betting on the games… that’s functionally a derivative. As we know from the housing crash, derivatives can trade in essentially infinite leverage as against the value of the underlying investment. I love ACKS but I don’t love it so much that I will work out a Roman-era derivatives trading model for gladiator games.

Assuming the gladiator has a 50% chance of winning each bout and that the 10% chance of death in a bout applies only to the loser, that means our prospective gladiator has a 5% chance of death in each bout.
Our theoretical gladiator has a 44.01% chance of surviving the 16 fights to reach 2nd level, a 27.74% chance of surviving through 25 fights to reach 3rd level, and and 17.48% chance of surviving to 4th level after 34 fights.
The “average” life expectancy is 13 fights - 48.77% of fighters will survive 12 fights or less, 48.77% will survive 14 fights or more.

This analysis doesn’t take into account any increase in fighting ability and survivability that comes with increased level, though. If fights are balanced up for higher-level competitors, then the victories should be worth more XP; if they’re not, then the loss chance should go down over time.

Also, it looks like a very good way to take L0 men up to 1st-level fighters; if a single won bout is worth 100 XP, then that’ll do it. The Thunderdome Mercenary Improvement Program looks pretty viable; 20% losses to turn the remaining 80% into veterans is better than you’d do on campaign, I expect. Morale might be a problem, though, and I suppose it is more expensive too, since there’s no spoils and pillaging to be had.

I wonder how much gold/XP you get from a fight which is until first blood (i.e. until teh first combatant reaches 50% or less HP)… This is still very risky at low levels (as the blow which could get you from 6 to 3 HP could get you to 0 HP as well), but safer at higher levels.