Aradia

Aradia is a character introduced in Souyaku Toaru Majutsu no Index.

[Spoiler] In reference to Aradia herself, her name has been explicitly noted as that of a figure from a famous witchcraft grimoire (namely Aradia, or the Gospel of the Witches). Said to be the daughter of Diana and Lucifer, Aradia was described as a goddess who shines in the dark night and "god of all witches", who supposedly took a physical body and descended to the human world to save the poor from the wealthy church. In the story, all witches' sabbaths are used to worship her and involve rituals meant to teach people how to resist oppression from the rich.

Aradia's full background is unknown, but she was described as a witch of the moon and light, and later described as though she was the figure from the book, the daughter of Lucifer and Diana who took physical form and descended as the goddess of all witches to save the ancient priestess of the night persecuted by the wealthy cross. On being addressed as "Maiden of Nuremberg" by Aradia, Anna referred to her as "the picture book witch who was pierced by its many spikes". [/Spoiler]

(Source: Toaru Majutsu no Index Wiki)