Dungeons 3

Dungeons 3 combines dungeon building with real-time strategy elements. Players are tasked with creating an underground dungeon for creatures to live in as well as defending their dungeon against invading heroes from the world above. They can also send creatures to the world above where they can take direct control of their units. The game's single-player campaign follows the story of Thalya, a dark elf sorcerer, on her quest to conquer the continent she lives on at the behest of the Dungeon Lord from the previous games. In multiplayer, players can either cooperate to play the campaign or compete against each other.

Source: Wikipedia, "[en.wikipedia.org/wiki/Dungeons_3 Dungeons 3]", available under the CC-BY-SA License.