This final victory represents the realization of the true Self, the end of all multiplicity, the steady experience of Oneness, and the passage from an ever-changing becoming to Pure Awareness or Being.
The Battle is symbolic of a spiritual struggle that is beyond the realm of day to day existence. The significance of the metaphor of fighting in mid-air.
The Devi Kills sumbha (representative of asmita or ego) by Piercing the asura with Her Spear Of Knowledge (Gnana).
The death of the ego or asmita, the false self, or limited ego-awareness, is nothing but the relinquishing of a limited identity.
But in losing this limited identity one gains an unimaginably greater one- that of The Supreme Being.