The Irregular at Magic High School, Vol. 27 (light novel) - Sudden Change Arc

As Minoru and the parasites continue their infectious escapades, Tatsuya is hard at work on his typeless magic—the sealing orb. If perfected, it could be used to capture parasites in a single move. Meanwhile, the war between the Great Asian Alliance and the New Soviet Union comes to a head, and the Soviets begin moving to invade Japan. Mobilized to intercept them are Masaki Ichijou and Shinkurou Kichijouji. How will the two fare against their sworn enemies?! One after the other, strategic-class magicians converge on the Land of the Rising Sun!