I didn't know what they were for.   In practice how does it work, how can it be useful to the modder?   I would like this to go beyond a mod and have 2 versions, one for modding and another to integrate into the game.

Keep in mind that Fanatics were originally meme units trainable from a special building (the Tavern) available only in some scenarios. They had like 1 Hack and 1 Pierce armor and were glass cannons. More glass, than cannons.

0 A. D. is not a game about World War II. Ancient battles were fought in the open, or in and around stone fortresses.

You have to investigate the templates, I guess.

Couple of pointers - Why do you have the tests folder? I suggest deleting it or properly using it to only test new functions. - You can compact UnitAI like this and only include functions you change/add. Note the ReRegister on the last line. After doing this you can delete the interface file for UnitAI aswell. - I think Stan has a valid point about optional elements, you forgot 2 unless they are intentionally not optional.

It would be nice if you could move earth with workers. That way you could build earth mounds or dig trenches in your defense line. (After all, this game is supposed to be historically accurate, and that was a common tactic at the time).

Yeah, I tried that already, and added a Roam distance to the soldiers, but it just gave me errors. Still trying to figure out why.