Kimi to Boku no Saigo no Senjou, Aruiwa Sekai ga Hajimaru Seisen

The planet is permeated with an energy known as Astral power, which is controlled by astral mages. The "Empire" persecutes people who demonstrate their ability out of fear of its corrosive influence. In order to escape their oppressors, the tortured mages established the Nebulis Sovereignty. Since then, the two countries have been engaged in a protracted war that has lasted for more than a century. Iska, a gifted knight, is imprisoned for committing the terrible act of releasing a witch from prison. After a year, the Empire's top officials decide to unexpectedly let him go on the condition that he find a terrifying wizard known as the "Ice Calamity Witch." Iska concurs, hoping to put a stop to the conflict. Unsurprisingly, Aliceliese "Alice" Lou Nebulis XI, the Ice Calamity Witch, likewise wants peace and is prepared to do whatever it takes to overthrow the Empire. The strands of fate bind Iska and Alice together, forging a link that goes beyond what can be explained by mere accident, as they both long for a crusade that will make the world into one without strife, grief, or pain.