Youkoso! Sukebe Elf no Mori e

Youkoso! Sukebe Elf no Mori e is set in Alfheim, a world inhabited only by female elves. While a war rages between the cast-out dark elves and the elves and high elves, the holy tree—mother and source of all elves—is losing its power and has stopped giving birth to new elves. However, they discover that a man from another world can save their tribes.

The protagonist is soon brought to this world. Since both factions have lost many members, the only way for them to multiply and win the war is to bear the protagonist’s children. Both factions approach him to make babies for their own sakes, and the protagonist falters on what to do when caught between the warring elven factions.