DARLING in the FRANXX

In the distant future, the world lies in ruins. Humanity survives in mobile fortress cities called Plantations. Within these cities, young pilots are raised in a place known as Mistilteinn-nicknamed the "birdcage"-cut off from the outside world and unaware of the sky’s freedom. Their only purpose is to fight in endless missions. Their foes are strange, colossal creatures called Kyouryuu, and the pilots battle them using giant robots known as Franxx. To these children, piloting a Franxx is the only proof they exist. Among them is a boy named Hiro, designated Code:016. Once considered a prodigy, he has now fallen behind, becoming an outcast. Without a Franxx to pilot, he might as well not exist at all. Then, one day, a mysterious girl called "Zero Two" appears before him. She bears two horns on her head, and her arrival changes everything.