The two Shaktis — Maya and Radha (residing in the heart). Maya is the transition from tamas to rajas and represents the lower three chakras, and then Mahamaya burns away all negative karmas at the solar plexus.
From here the Devi chakra begins at the heart, the transition between rajas to pure sattvik energies — pure consciousness. When Shiva goes through the process of purification, he first chooses Maya and often gets trapped in it. If he keeps the doors of his heart closed, self-realization doesn’t come to him. He keeps going back in loops. He is powerful and is a provider, yet he is confused at the heart chakra. If he chooses to open the doors, he gets elevated with his Sattvik Shakti and becomes pure consciousness himself. He becomes God. Else if he continues to drop back, he gets trapped in Maya and the loops of rebirth. If he chooses his Sattvik Shakti, he chooses Moksha — the separation between God and him ends.
What if he doesn’t choose Sattvik Shakti? Prakriti removes Shiva that refused to elevate and replaces his head with Gajanan/Varaha/Narsimha mukha of pure consciousness. Here she is Chinnamasta, cutting her head off as a sign of sacrifice where she is letting her Shiva choose the Maya of lower chakras.