Aztec Wars

Three civilizations compete for territory, and the competition is economic before it is military. Every faction starts with basic houses that generate money and basic troops, but advancement requires reinvesting: houses become villages, villages become cities, cities become fortresses, each tier unlocking units and structures the lower tiers cannot field. Mines and farms expand the income base; defense towers protect the investment; specialized buildings — a bear's cave for war bears, for instance — give each civilization's army capabilities that the others cannot simply replicate. Victory goes to whoever manages the economic logic of expansion without overextending the supply lines that keep it running.