Sentou Yousei Shoujo Tasukete! Mave-chan

Japanese Title: 戦闘妖精少女 たすけて！メイヴちゃん

English Title: Fighting Fairy Girl Rescue Me Mave-chan

Plot
Rei goes to an anime convention and ends up in a world created by the desires of anime fans. Rei doesn't know how to get back and the world starts to collapse because the convention is coming to a close.