Who is Maa Chintpurni Devi:
After defeating many fierce demons, Maa Parvati, along with her assistants Jaya and Vijaya (also known as Dakini and Varini) went to bath in the Mandakini River. Maa Parvati felt very happy and a lot of love was rising in her.
Her complexion darkened and the feeling of love took over completely. His friends, meanwhile, were hungry and asked Parvati mata to feed them. Parvati asked them to wait and said she would feed them after a while and started to walk.
After a while, Jaya and Vijaya appealed to Maa Parvati again, telling her that She was the Mother of the Universe and that they were her children, and asked to be fed quickly. Parvati Devi replied that they should wait until they get home. The two assistants could not wait any longer and demanded that their hunger be satisfied immediately.
Compassionate Parvati laughed and cut off her head with her fingernail. Immediately, blood gushed in three directions. Jaya and Vijaya drank the blood from two directions and the Goddess herself drank the blood from the third. Ever since Maa Parvati Devi cut off her head, she has been known as Maa Chinnamastika.
She does this to fulfill the wishes of her children, her devotees, thus also known as Mata Chintpurni.