Lostbelt

Lostbelt is a major story arc within the mobile game Fate/Grand Order, developed by Delightworks and Lasengle, and published by Aniplex. It follows the protagonist, a Master in the Chaldea Security Organization, and their Servant allies as they travel across different alternate timelines, known as Lostbelts. These Lostbelts are described as branches of history that were supposedly erased from the proper flow of time.

The core conflict of the Lostbelt arc revolves around the threat posed by the Alien God, a cosmic entity that seeks to overwrite the current timeline with its own version. To achieve this, the Alien God's forces, known as the Crypters, have been tasked with establishing and protecting these Lostbelts. The protagonist's mission is to invade each Lostbelt, defeat its King and Crypter, and ultimately restore the proper timeline.

Each Lostbelt presents a unique, often grim, depiction of history. These timelines diverged at a critical point, leading to vastly different societal developments and often harsh living conditions for their inhabitants. The player must fight against the established order of each Lostbelt and confront its unique challenges and Servants. The story explores themes of survival, the definition of history, and the morality of erasing entire worlds, even those deemed "lost" or "unfit" by the established timeline. The arc is characterized by its darker tone compared to previous story arcs and introduces many new characters and Servants.