Resume : he action of the first cycle of Okko takes place at the far end of the known lands of the Empire of Pajan. Pajan itself is a vast and diversified island, surrounded by a multitude of archipelagoes. Its name is derived from that of its Imperial Family. Though the Pajans have reigned for a millennium, in the last few decades three major families—the Ataku, the Boshimon, and the Yommo—have called into question their legitimacy and now refuse to cease their battles against the Imperial Family. These power struggles have destabilized the Empire, and famine and catastrophes follow one another. This period of chaos is commonly called the Era of Asagiri (the Time of Mists).

The Okko series begins in the middle of this tumultuous period, in the year 1108 of the official calendar. The way of life and various habits of the inhabitants of the Empire of Pajan are rather close to those of medieval Japan. However, one major difference is a great technological revolution that appeared a few centuries ago: the exo bunraku, colossal combat armors handled from within by marionettists. Their use has radically changed the ancestral art of war in the Pajan Empire. The Ataku family has taken the lead in the construction and the handling of these frightening machines of war.