The story of how the 502nd Joint Fighter Wing (The "Brave Witches") formed, prior to the events of the Brave Witches anime.

Ayaka has a dear friend named Hiroko. Hiroko suddenly vanishes from Ayaka’s life, saying that she must save someone important to her. Since that time, Ayaka hasn’t heard anything from Hiroko, until a girl’s corpse is washed up on shore, and she’s holding a letter from Hiroko which reads: “Come save me.” Ayaka sets off to save her best friend, and ends up in a mysterious school where everything seems too good to be true. Is it?

From ADV Manga:

The prestigious Aoi Academy caters to an elite collection of young magic users. But 17-year-old Kazuki Shikimori is a student who passes muster in name alone. He is the youngest in a long line of sorcerers, but the family's long-running talent for the black arts ended with this average student. That doesn't stop the female population of Aoi Academy from vying for his attention, though! His impeccable DNA will start a teenage war of lovesick girls!

From Renzokusei Scans:

Tachibana Kazuya, Kumazawa Daigo, and Niinuma Hiroko all want to be popular. But they don't know how to do so! So, they try and create a club to research and find out how to become popular.

Senou Natsuru is a normal high school boy. One day he wakes up to find himself turned into a girl. A stuffed tiger "Harakiri Tora" comes to life and tells him to fight as a female psychic fighter "Kämpfer". Having no idea about what's going on, Natsuru is involved in the battles against other "Kämpfer".

Kämpfer is German for fighter.

The Kirionira are the demons that live in another dimension and invade the human world through people's dreams. The only defense humanity has against the demonic assault are the hunters who rely on their sex drive as a source of power to fight against them.
Riku Yoichi came from a long line of hunters and had high amounts of sexual energy which allowed him to be a great hunter. He moved away from his home town after middle school to demolish the Kirionira and was successful in finishing off the king and ending the battle forever. However, the peace came at the price of Yoichi losing his sex mojo.
Returning back to his home town, he soon learns that the demon invasion was not over, but without his sex drive, he is helpless to fight back. He tries convincing his childhood friend Namba Midori and her female classmates to get him sexually aroused, but they want nothing to do with it.