The manga Fate/Grand Order From Lostbelt is an anthology series that delves into the lives and perspectives of the Crypters, the seven rogue Masters who betrayed Chaldea following the events of the first part of the game. Their defection sets the stage for the Cosmos in the Lostbelt arc, where Proper Human History has been bleached from the Earth and replaced by seven divergent timelines known as Lostbelts, each ruled by a powerful king.

The story does not follow the protagonist Ritsuka Fujimaru. Instead, it provides intimate vignettes exploring the backgrounds, motivations, and inner conflicts of the antagonists who serve the Alien God. The initial chapters focus on the Crypters, including Kadoc Zemlupus of the frozen Russian Lostbelt, Ophelia Phamrsolone of the Scandinavian Lostbelt, and the other members Akuta Hinako, Scandinavia Peperoncino, Kirschtaria Wodime, Beryl Gut, and Daybit Sem Void. Later chapters expand to feature other key figures from the Lostbelt arc, such as the Lostbelt Kings and their retainers like the Fairy Knights of the British Lostbelt.

The narrative is structured as a collection of standalone chapters rather than a linear plot. Notable arcs include chapters focusing on a Crypter's past before joining the defunct Chaldea, their private thoughts during the campaign to eliminate the Lostbelts, and their relationships with their Servants. Some chapters depict their final moments or their internal reactions to the failures of their comrades. The anthology also includes stories set outside the main conflict, such as the special chapter Miss Olga Marie, which provides additional context for the former director of Chaldea.

Written and illustrated by Nakatani, the manga serves as a companion piece to the game, intended to enrich the main scenario by filling in narrative gaps and giving voice to the antagonists whose perspectives are largely unseen in the original interactive story.