Zettai Saikyou ☆ Oppai Sensou!! ~Kyonyuu Oukoku vs Hinnyuu Oukoku~

Bustchest continent is at war: the Big Breasts and Flat Chest kingdoms fight to determine once and for all which size is better. Haruto, the protagonist, loves all sizes equally. According to the Breasts God, he has a special power which can save the continent, so without a second thought, Haruto starts his quest as a breasts-loving messiah.