The oldest magical girl of the 3. The typical elder sister character that portrays her.

Ai, Rin, and Meg are magical soldiers who battle the evil Yuragi infesting the streets at night. The usually solitary Yuragi, attacking girls at random, have been collaborating towards an unknown goal. In the center of it all is Shin and his daughter Mayu, who Rin gave birth to after he raped her. 
(Source: HentaiCrunch.com)

In a certain town, there were consecutive phantom assaults. Because the incidents were extraordinarily, there was a rumor that a ghost or supernatural creature caused them. The students in the school which Akitoshi went to were frightened. One day, an unknown girl appeared in the school. However, all the students except Akitoshi thought they had known her. Feeling strange, he shadowed her in order to investigate her but he lost sight of her. At that moment, he heard the scream of a woman from the nearby material yard and went to the place where the scream came from. There he found the beautiful girl of the school, Mikage. Mikage was surrounded by monsters "Yuragi" (fluctuation), and she was hanged naked. Yuragi noticed Akitoshi and began to attack him. Then, the fighter, Ai, appeared and cut them down. 
Akitoshi stared at Ai. What was her true character, an enemy or an ally? 
(Source: AnimeNfo)

Megu