Infinite Stratos

Japan engineered an armed powered exoskeleton "Infinite Stratos" (IS) and it became the mainstream of weapons. Since only women can operate IS, women dominate the society over men. Orimura Ichika is a 15 year old boy and accidentally touches an IS placed in the IS pilot training school. He is found to be the only man who can operate IS and forced to enter the training school. Ichika's busy school life surrounded by girls has begun.

Hybrid x Heart Magias Academy Ataraxia

Hida Kizuna possesses the HHG (Heart Hybrid Gear) ability, but it is not strong enough to make him particularly important. His older sister calls him to transfer to a strategic defense school, where many of the students (many of which are large-breasted girls) use their HHG abilities to fight invaders from another world while wearing extremely skimpy pilot outfits. Kizuna's fighting ability doesn't measure up, but his sister has another plan; getting the girls to have erotic experiences with Kizuna, so that it will allow them to replenish their energy or power-up. It looks like his new school life is going to be full of embarrassment! (Source: MangaHelpers)

Qualidea Code

The anime takes place in a world where humans are continuing to fight a war against an enemy called UNKNOWN. UNKNOWN invaded several decades ago, and children entered a cold sleep to escape the invasion. When the children awoke, they found themselves with supernatural powers. The children set up defense cities in Tokyo, Kanagawa, and Chiba in order to protect the country from the UNKNOWN, who appear through the Tokyo Bay Gate. (Source: Anime News Network)

The Asterisk War

Invertia (meteor storm)… an unprecedented disaster that struck the world during the 20th century. Because of this disaster, numerous cities around the world were destroyed. However, within the meteor, an unknown element called mana (the all-encompassing element), was discovered, which allowed human technology to make rapid strides. This also gave rise to a new species of human born with unique skills – the Star Pulse Generation (Genestella). The setting for the world’s greatest comprehensive battle spectacle, the Festas (Star Warrior Festivals), is an academy city above the water surrounded by six academies called Rikka also commonly known as Asterisk. Having transferred into Seidoukan Academy in order to fulfill his own wish, scholarship student Ayato Amagiri swears he too will fight in this city. Burning souls race… The curtain rises on this school battle spectacle! (Source: Crunchyroll)

Absolute Duo

The story begins with Blaze — a weapon that is the manifestation of a human's soul. Tooru Kokonoe happens to be qualified for this, but for some reason his Blaze is not a weapon, but a shield. Moreover, he enrolled in a school that teaches combat skills, and thanks to the school's Duo partner system, he ends up living with a beautiful silver-haired girl. (Source: Anime News Network)