All sentient beings possess Buddha-nature which means primordial wakefulness free from thought constructs present inthe mind. By virtue of possessing Buddha-nature, one is able to become an enlightened one. But in order to realize Buddha-nature, the precious human body is needed. The precious human body enables the accumulation of merits and wisdom which are needed for the realization of the enlightenment.
Because of this Buddha-nature of our mind an enormous pantheon of Vajrayana deities is being manifested in order to tame sentient beings and assist the practitioners in eliminating their obstructions to enlightenment. In Tantric Buddhist tradition we visualize Buddhas, Yidams, Dakinis and Bodhisattvas as enlightened states to be attained. The practice of deity yoga is compatible only because we have Buddha-nature.