For the embodiment of the materialization of the magic girl's soul, the incubator borrows the entropy element to separate the growing girl's soul from her body and become a real individual.

Uses: the main function is to transform, let the magical girl use the powerful power different from ordinary people, and also restore physical trauma, preserve the body, explore the smell of witches and so on.

Witches hold a lamentation, alias: GS, sad seed.

It is the final destination of the magical girl after she runs out of magic, and can be used to absorb the polluted air of SG. If too much turbidity is absorbed, new witches will hatch. So one of the tasks of the incubator.

The magic consumption of the magical girl or the despair of her spirit will lead to the gradual turbidity of SG. If SG is completely polluted, SG will be broken and transformed into GS, the soul of the magical girl will completely lose control of her thoughts, and the witch will be born from GS, and her body will become an empty shell without soul. At this point, the magic girl died.

To put it simply: ordinary girl → sign a contract with the incubator → fight against the witch as a magical girl → run out of magic/fall into despair → become a witch → be eliminated by other magical girls → be eliminated by the incubator/overuse and be reborn as a witch again.