Short answers, pulled from the story.
The Kuril Islands are summits of stratovolcanoes formed by the subduction of the Pacific Plate under the Okhotsk Plate. This tectonic activity created the Ring of Fire and the Kuril Trench located 80 kilometers east of the islands.
The Ainu people inhabited the Kuril Islands from early times, with records existing from the Kamakura period to the Muromachi period. The name Kuril originates from the autonym kur used by the Indigenous Ainu meaning man.
Soviet forces invaded the North and South Kurils between the 18th of August and the 31st of August 1945. The Soviets expelled the entire Japanese civilian population of roughly 17,000 by 1946 following this invasion.
Japan maintains a claim to the three islands of Kunashir, Iturup, and Shikotan along with the Habomai Islands. These territories are collectively called the Northern Territories in the context of the ongoing dispute.
Extensive kelp beds surrounding almost every island provide crucial habitat for sea urchins, various mollusks, and countless other invertebrates. Walleye pollock, Pacific cod, and several species of flatfish are of the greatest commercial importance to the region.