Reus is a game where you control four giant elements - forest, mountain, ocean, and swamp - to shape a planet and its inhabitants. These giants work together, each with unique abilities that bring different plant and animal life, minerals, and upgrades. When food is available, humans start settling and growing in the area influenced by the giants. The growth of these human settlements depends on the benefits provided by the giants.
As you progress through the game, the humans' behavior changes from peaceful settlement to aggressive expansion, attacking other human settlements. In response, the giants can unleash their natural powers to punish them. You must balance the needs of the giants and the humans to create a harmonious planet.