Sentou Yousei Shoujo Tasukete! Mave-chan

On his way to a Stratos 4 convention Rei goes to the bathroom for a break.

Instead he finds himself in the Yukikaze world, where Maeve, Super Sylph, Sylphide, One-chan, and Two-chan fight to stay alive.

This world was created by the desires of anime fans and can only exist as long as they remember their beloved characters.

But he must hurry, the convention is ending and so is this world.