Her Majesty's Swarm: Volume 4  (English, Paperback, 616th Special Eiri)

With three countries already having fallen to the might of the Arachnea, Grevillea sets her sights on the next target: the Nyrnal Empire, the land of swooping wyverns and a supreme military power. To reach the Nyrnal Empire, Grevillea must first acquire the Eastern Trade Union. Its capital of Khalkha is a hedonistic paradise...but will Grevillea and Emperor Maximillian's clash for supremacy make its streets run red with blood? The Arachnea and the Empire, the last two great powers on the continent, wage war for the right to rule! With Grevillea's secrets dragged out into the light, the story hurtles toward its climax!