Extreme Hearts

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!

The story takes place in Shibuya. Ryuhei had always looked up to his older brother as a child. Even after witnessing his mysterious death, Ryuhei grows up to be a cheerful high school student. One day after his daily kickboxing practice, he is bitten by a strange creature calling itself Tris. That night, an unusual dream bothers his sleep. As the rumored "Drops" circulate around the city, Ryuhei is confronted with a force of twisted desire. What is it that awaits him beyond that?

Earth faces an unprecedented threat from an invasion by the mysterious Kiseichuu. The Kiseichuu feed on human sexual energy, also known as “H-energy,” and weaken the human population. High school student Retto Enjo is a member of the hero group HxEROS, who fight together to save the earth from the Kiseichuu.

Siblings Tatsuya and Miyuki enroll at Magic High School, where Miyuki's honors status comes between her and her underachieving older brother.