In the Vedic pantheon, Indra was the king of the gods. He was depicted as a warrior and associated with storms and with thunder, like the Norse god Thor or the Greek Zeus. In one story, he is depicted as slaying the dragon Vritra who was holding back the waters. When the dragon dies, the first rains fell on the earth and everything began to grow.
Purusha on the other hand is the primordial giant who was sacrificed to bring the world into existence. When he was sacrificed the gods came from his body as well as the divisions of society. The Brahman priests came from his mouth, the warriors from his arms, the merchants from his thighs, and the servants from his feet. In this origin myth there is the suggestion that everything is originally a unity, that everything comes from the same source. There is also a reinforcement of the central place of the Vedic sacrifice.
The stories of Indra in this context emphasize the role many different gods play in the creation and maintenance of the world. Each god or goddess has his or her own function. On the other hand, Purusha represents a belief in the unity of the world. This is later developed in the Upanishads to suggest that all things are ultimately One, and that through meditation one can experience this unity of all things. This connection is also strengthened by the recognition that later the term purusha came to refer to the immortal, unchanging divinity within that is discovered through yoga.