Acharya Prashant explains that the ego is essentially a sense of impurity, incompleteness, and restlessness. He describes it as a continuous tension and a feeling of being in danger or unsettled. This sense of incompleteness is an inevitability of being born into a body form. While the core of this 'hollow' or hunger is common to all, individuals differ in how they attempt to fill it, which defines the different types of ego based on the three gunas.