Dungeon de Tatakai Tsuzukete 20-nen no Doutei Yuusha, Chijou ni Modottara Danjohi 1:1000 no Sekai Datta

The Virgin Hero Who Fought in the Dungeon for 20 Years Returned to the Surface Only to Find the Population of the World Has Dropped Drastically · with a Male-to-Female Ratio of 1:1000