Senran Kagura

In the Taiheimeji era, the Tokugawa shogunate values breasts highly, equating them with wealth and status. The Manyu Clan, government allies, know secret techniques for breast enhancement, detailed in a scroll. Chifusa, the clan's heir, flees with this scroll, rebelling against the oppressive norms set by her clan.

Every few years, beautiful female warriors from across the land compete in the Queen's Blade Tournament to become the ruler of the land. It's a series that loves violence as much as it hates clothes and complicated plots.

One day, humanity was invaded by another world. Having experienced that battle, known as Other World War I, humanity moved to marine floats, built for emergency evacuation purposes, as soon as Other World War II began. It's around that time that Kizuna Hida is summoned by his elder sister and visits the Strategic Defense Academy Ataraxia where he meets Aine Chidorigafuchi, a girl who uses Heart Hybrid Gear Zeros to fight the otherworldly enemies. He has a tough time dealing with her, but when her Gear runs out of energy, the only way to get it back in action is to do something lewd to her!

In the future — in a world mostly submerged under water — the 19-year-old Sumeragi Aika goes to college while training as an agent by assisting in Aida Gozo's salvaging business.