Machines in Horizon Zero Dawn dominate the world. They resemble many different life forms on Earth such as Birds, Dinosaurs and other Fauna. The Machines serve as technologically advanced tools for collecting resources, building, surveying, and even defending the land.
After the fall of human civilization, The Machines have risen to live in co-existence with natural animals on Earth. Many of the Machines are hostile towards humans and little is known as to why they dominate the land. It seems their purpose on Earth is to protect it however recent events and sightings of corrupter machines and their agenda behind creating corrupted machines may change how the machines behave towards other life forms on Earth.