Procedural generation of non-player characters in massively multiplayer online strategy games

This paper presents a coevolutionary framework for procedural generation of NPCs in MMORTS games. In this context, players need to defeat environmental troops in battle to gather resources and achieve their goals. The benchmarked game has several balance problems related to these battle activities, mostly caused by the handcraft design of complex game content. To solve this problem, the algorithm takes player modeled heroes as input and returns a solution evolved to win. By this way, the players need to think better in a new way to conquer the victory, adding new levels of challenge, keeping the game enjoyable. We present a new mathematical model to evaluate the solutions, based only on the number of soldiers on the input and output, making it easy to extend to other contexts. The results show it is possible to procedurally generate thousands of new efficient and fair builds, without violating the game rules. Moreover, our analysis of the results was able to identify unbalanced characteristics in the game design and we suggested simple way to fix it.