Kyoryuu, often referred to as the Klaxosaurs, are mysterious and formidable creatures in the anime series Darling in the Franxx. They serve as the primary antagonists, attacking humanity's settlements and forcing people to live in mobile cities called Plantations. The origins and motivations of the Kyoryuu are gradually revealed as the series progresses, playing a crucial role in the story's exploration of survival, evolution, and the relationship between humans and nature.