It's a rather simplified arena tester: two monsters are introduced at 6 squares apart, and try to kill one another. When one dies, another monster of the same type as the one that died is introduced. This continues until a max number of fights is hit (1,000 for small numbers in the input file; it's only 51 for every combat-capable monster in the game). The value of each monster is equal to the value of the monsters it kills, divided by the number of times it dies (value is not 'book' value -- it starts at book value, and then computes value 20 times, each time using the value from the last computation). There are probably some bugs; in particular, I know spellcasting doesn't work.
Using max quality mundane troops (adamantine elite), it turns out, fairly unsurprisingly, that the most cost-effective units in the game are spearmen. This somewhat overstates their true value, as a city that can produce adamantine elite units probably has a production of 30+ and thus wastes production on spearmen. Also, it's good for cheap units to be cost-effective, the main reason for expensive units is because of the stack limit of 9. The units that are terrible are also unsurprising, most of them are uncommon summons, the worst mundane unit is beastmen manticores (note: cost is the cost the game is charged to put things in a lair; this occasionally differs from summon cost).
The strongest unit (absolute) is death knights.
It's probable there are bugs (fight.txt is actually a c file)
Using max quality mundane troops (adamantine elite), it turns out, fairly unsurprisingly, that the most cost-effective units in the game are spearmen. This somewhat overstates their true value, as a city that can produce adamantine elite units probably has a production of 30+ and thus wastes production on spearmen. Also, it's good for cheap units to be cost-effective, the main reason for expensive units is because of the stack limit of 9. The units that are terrible are also unsurprising, most of them are uncommon summons, the worst mundane unit is beastmen manticores (note: cost is the cost the game is charged to put things in a lair; this occasionally differs from summon cost).
The strongest unit (absolute) is death knights.
It's probable there are bugs (fight.txt is actually a c file)