Aku Sei Jutai Anira to Uira

The year was 20XX. Earth faced an unprecedented crisis.
All at once, enormous "domes of evil flesh" appeared in every major city.
The monsters that emerge were called Conjurom.
Earth males were slaughtered, while the women were taken for breeding,
and there was no weapon powerful enough to stop them.

The invasion heralded the end of our way of life.
But the aliens seem to be looking for something, or someone,
among the human population. They don't just want women...

Conjurom are looking fo "magical girls"-----

[From DLsite English]