The United States, from its founding in 1776 to its existence in 1778-2024, endured until the war of 2025. Its spirit and culture continue to live on and still exist today. Fast forward to 2142, a century after World War 3, the Unified Commonwealths of America is one of the greatest and last nations representing the old world. The UCA operates in secrecy, separate from the four kingdoms of Planet Earth/Remnant. Over the past 100 years, the UCA has been observing these kingdoms, finding them both futuristic and primitive, with conflicts stemming from the old world. Within this world, humans and Faunus coexist peacefully, corporations contribute to infrastructure, and interstellar travel has been achieved. The UC will soon need to liberate Remnant and uphold the principles of democracy and freedom.
In the year 2023, Chaldea Security Organization has completed the Fate project and has assigned one of their Security Officers as a Master to a Heroic spirit with the goal of destroying or retrieving the Holy Grails when and wherever they might appear. Stopping whatever threats are summoned in the process from causing any further harm, and preventing the destruction of Humanity.