Both words describe a family of divine beings, the Æsir is the pantheon of the principal Norse gods, and Asuras are a group of Hindu deities. Each group is set up against another group of gods; the Æsir warred with the Vanir, whereas the Asuras oppose the Devas. In Norse mythology the Æsir are generally approved of (and worshipped) while the asuras have a more negative reputation in the Indian religions. However, the use of ahura to refer to the greatest god of Zoroastrianism implies that the word once had more favorable connotations. In the earlier Vedic literature also those we know of as Devas, like Indra, are called Asuras.
The relationship between the Æsir and Vanir parallel the Asuras and Devas in another way; like the Æsir, the Asuras were associated in Vedic myth with human phenomena (contracts, the arts, fate), while the Vanir, like the Devas, are associated with natural phenomena (such as Njord and Freyr, associated with fertility).
Wiki language association:
The cradle of mankind becomes clearer, and more clear . . .
But the Norse G^ds were not on a snipe hunt for the elixer of immortality!
Mind is the rider.