Mahakali's origin is contained in various Puranic and Tantric Hindu Scriptures (Shastra). In these She is variously portrayed as the Adi-Shakti-Goddess Durga, the Primeval Force of the Universe, identical with the Ultimate Reality or Brahman. She is also known as the (female) Prakriti or World as opposed to the (male) Purusha or Consciousness, or as one of three manifestations of Mahadevi Durga (The Great Goddess) that represent the three Gunas or attributes in Samkhya philosophy. In this interpretation Mahakali represents Tamas or the force of inertia. A common understanding of the Devi Mahatmya (Greatness of the Goddess) text, a later interpolation into the Markandeya Purana, considered a core text of Shaktism (the branch of Hinduism which considers Devi Durga to be the highest aspect of Godhead), assigns a different form of the Goddess (Mahasaraswati, Mahalakshmi, and Mahakali) to each of the three episodes therein. Here Mahakali is assigned to the first episode. She is described as an abstract energy, the yoganidra of Vishnu. Brahma invokes Her and She emerges from Vishnu and He awakenes. Thereafter, She kills the demons Madhu-Kaitabha. She is the Goddess of time.