Durgaa and Mahishaasur Battle : Difference Between Asur and Raakshas - Are They Not Both Demons?

To majority of Hindu and those who read Hindu scriptures and stories, Asur, Daitya and Raakshas mean the same, that they are demons. But several scholars are of the opinion that an Asur and a Daitya and a Raakshas are not the same. They are different.

(1) The primary difference is that Asur resides in the netherworld or underground and a Raakshas live on the earth.

(2) Asur are the enemies of Devtaa or demigods and Raakshas are the enemies of human beings and saints.

Raakshas
Some scholars are also of the view that Raakshas were the protectors of the forest and came into conflict with human beings who wanted to clear forest, cut trees and wanted to exploit the nature.

It must also be noted that majority of the episodes of battle between Raakshas and human beings take place in forest. It looks like the humans were invading their space and it is when they retaliated.

Raakshas are chiefly mentioned in the Raamaayan and Mahaabhaarat like Taadakaa, Shoorpanakhaa, Kumbhakarn, Hidimbaa, Ghatotkach, Bak etc.

Not all Raakshas are of evil nature, there are several instances in scriptures when humans have taken the help of Raakshas. Like Gahatotkach in the Mahaabhaarat.

Another noteworthy aspect is that majority of the Raakshas got the form due to a curse and finished their curses when they are killed by an incarnation of Vishnu, for example Hiraykashyap, Hiranyaaksh, Raavan, Kumbhkarn, Shishupaal etc.

Most Raakshas don't challenge the authority of the Tri-Moorti - Brahmaa, Vishnu and Mahesh.

Asur
If the above said difference between Asur and Raakshas is to be accepted then Asur are chiefly mentioned in the Puraan. They always attempt to dethrone Indra and other Devtaa from Heaven. Vishnu, Shiv, Shakti or Kaarttik helped the Devtaa to defeat the Asur.

It must be also noted that Asur also challenge the authority of Vishnu, Shiv and Brahmaa the Tri-Moorti.

Yet again not all Asur are bad. For example there is King Bali who was not at all bad.

Most Asur also have supernatural origin and supernatural powers. Interestingly they acquire most these powers by performing Tapas and austerities dedicated to the Tri-Moorti, especially Brahmaa or Shiv. In this regard this is noted that all Asur were Shiv Bhakt except Prahlaad and Vibheeshan - they were Vishnu Bhakt.

There are also demons that fall into the category of both Raakshas and Asur. The best example is that of Raavan.