Previously, I tried to make an AI player much larger, like increasing the population limit, making them build more clusters of buildings in different places to simulate an empire with multiple cities, but I could only modify the C++ files by changing a few values. I'm not even a programmer; modifying JavaScript files is beyond my capabilities.

I’m actually not very familiar with coop-mode or Archon mode, so I wasn’t referring to those. As far as I know, those modes are about multiple human players controlling a single player slot. What I’m talking about is AI-only. Several separate AI players of the same civ, each with their own economy and territory, but behaving outwardly as one large coordinated bloc — sharing the same diplomacy and roughly the same strategic stance toward other players. The idea is simply to create the feeling of a massive empire without having to make one civilization overwhelmingly strong or unbalanced.

You're talking about the coop-mode? Something like Archon mode in StarCraft 2?

I’m exxplore the idea of representing a large, multi-regional empire in 0 A.D. by using several allied players of the same civilization. Something similar to how some historical empires often worked for example, loosely coordinated regions within the Achaemenid Empire, the Habsburg realms, or other multi-centered polities that acted as one bloc toward the outside world. In gameplay, this concept could be interesting, but there’s a major limitation: even if the players are allies, each AI still makes its own diplomatic and military decisions. They may treat other factions differently, choose different war targets, or behave in uncoordinated ways. So the “empire” doesn’t actually act like a single entity. My idea: Would it be feasible to introduce an optional AI mode, separate from standard “ally” behavior, where multiple players could: automatically share the same diplomatic stance toward all other players, follow the same external military target or general direction of attack, and optionally share the same color to reinforce that they are parts of the same overarching power ? The goal isn’t to merge them into one player, but to let them behave outwardly like one unified empire while still being technically separate players. I’d like to ask the developers and AI experts whether something like this is achievable within the current AI system, or if it would require deeper changes.

Pay attention to the story next time and I promise you will love its complexity lol