Glest

Description
Glest is a 3D real-time strategy game with gameplay similar to WarCraft 3. In a medieval fantasy world, proponents of Magic are in conflict with those who feel that Technology has all the answers. You choose one of these factions and fight rivals by building cities, harvesting natural resources and building troops. Eight maps are provided with different settings, incorporating rivers, islands and mountains.
Magic must defeat the opposition by using magic spells (such as fire and healing) and summoning demons. Technology must crush the enemy with force of arms and industry.
There is support for up to four players at once. Glest is also very user-extendable, with all the data for the units and tech trees stored in XML files that can be modified by the player.