ファウスト

The protagonist of "Faust". She is bored with life as she has experienced every hedonistic pleasure there is thanks to Mephisto's magic. Eito and Tale are called in to deal with Faust's ennui as her lazy inaction in the long term would threaten the very nature of the story itself.

Mephistopheles initially wields Faust like a human club when fighting worms, but after Faust regains motivation she destroys worms using her magic lantern.

 Unlike the other characters, Faust deliberately allowed Grimoire to corrupt her with a parasitic worm in the hope it would give her new exhilaration after the worm's effects on personality took root. However the experiment backfired as Faust's lack of stimulation from excessive hedonism was magnified instead.

It is through the participation of the preparation for the Walpurgis Night Festival that Faust learns the value of creating and defending a venture through hard effort, as well as the feedback which comes from others for persevering to the end. This allows her to break the hold of the parasitic worm and regain her original motivation for summoning Mephistopheles.  

Through Mephisto's magic, Faust has expertise of the sexual pleasures of the female form. The inhabitants of her world keep their distance when she's out and about because she's liable to ask Mephistopheles to use magic to forcibly strip a woman and charm her to Faust's will. /