Durga or Kali
In Vedas, Durga, meaning "the inaccessible" or "the invincible"; Bengali or ma durgā, meaning "Mother Durga") "one who can redeem in situations of utmost distress" is a form of Devi, the supremely radiant goddess, depicted as having eight arms, riding a lion or a tiger, carrying weapons and a lotus flower, maintaining a meditative smile, and practicing mudras, or symbolic hand gestures. Kali is considered by an aspect of Durga. She is thus considered the fiercer, demon-fighting form of Shiva's wife, goddess Parvati. Durga manifests fearlessness and patience, and never loses her sense of humor, even during spiritual battles of epic proportion.
Srila Bhaktivinoda Thakura in his purports on Sri Brahma Samhita, especially in 5.41 and 5.44, clearly describes Sri Durgadevi as sakti-tattva, who is related to the original sakti, Rama, as Lord Siva is related to Maha-Sankarsana.
It is described that as Lord Sankarsana gets reflected in the water of the Causal Ocean, and His reflection becomes Lord Sambhu, a tattva on his own, similarly Laksmidevi, or Rama, who is service the lotus feet of Maha-Sankarsana, gets reflected in the Causal Ocean thus manifesting as Sri Durgadevi. That is why Durgadevi is sometimes called jagal-laksmi, or 'Laksmi of this Universe".
There are a few references which shed some more light on the position of Srimati Durga devi:
"The Brahma-samhita says, chayeva yasya bhuvanani bibharti durga. Durga is not different from yogamaya. When one understands Durga properly, he is immediately liberated, for Durga is originally the spiritual potency, hladini-sakti, by whose mercy one can understand the Supreme Personality of Godhead very easily. Radha krsna-pranaya-vikrtir hladini-saktir asmad. The mahamaya-sakti, however, is a covering of yogamaya, and she is therefore called the covering potency. By this covering potency, the entire material world is bewildered (yaya sammohitau jagat). In conclusion, bewildering the conditioned souls and liberating the devotees are both functions belonging to yogamaya." (SB 10.1.69 add. notes)