In Reus the player (presumably a planet) controls four giants to help shape the planet and its human inhabitants. These four elemental giants (forest, mountain, ocean, and swamp giants) work in a symbiotic manner, as do their abilities. Each may bring unique plant and animal life, as well as minerals, all of which may be upgraded with aspects (i.e. bonuses). When food is available, humans may begin to settle and grow. How these humans evolve will greatly depend on the benefits bestowed by these giants within the borders of a human settlement. If they grow too greedy, they will start attacking other human settlements, to which, the giants may unleash their terrible powers of nature to punish them.