I wish to support the idea, by mobilising more evidence, which proves the idea.
1. jhArkhand State has a language called 'Asuri' spoken by about 16,000 people. Here is a link: Click to go to the site of ethnologue. .
I also quote its details for your ready reference:
A language of India
ISO 639-3: asr
Population 16,600 (2001).
Region Jharkhand, southern Palamau, northern Ranchi, Gumla and Lohardaga districts of Chotanagpur Plateau; Chhattisgarh, Raigarh District, Jashpur area; Maharashtra; Orissa, Sambalpur District; West Bengal.
Alternate names Ashree, Assur, Asura, Maleta
Dialects Brijia (Birjia, Koranti), Manjhi.
Classification Austro-Asiatic, Munda, North Munda, Kherwari, Mundari
Language use Also use Sadri [sck] or Bengali [ben].
Language development Literacy rate in L1: Below 1%.
Comments Asur and Birjia are both Scheduled Tribes. Hindu, traditional religion, Christian.
Asuras were thus people living in jharkhand, south bihAr, West-bengal, Orissa, chattisgadh, (etc.).
They were not real demons. They were just humans, speaking the Asuri language.
While the South moving rAma and his Company spoke Sanskrit or allied languages of the Indo-European Group, the asuras might have spoken Asuri, a language of Austro-Asian group.
Their culture might have been slightly different from the culture of the culture of rAmA and Co.
I am using the word 'slightly' because there are some common elements between "sura" and "asura" cultures.
According to Hindu mythology, both suras and asuras are half-brothers, born to the same father 'kasyapa' and different mothers 'aditi' and 'diti'. Hence, the animosity seems to be more of a 'fraternal' nature, rather than 'racial'.
We have anotehr version. The suras and asuras arrived into India from Iran. Zend Avesta has some references to these sura and asura differences. (According to zend-avesta concepts, asuras were good people and suras were not so good. The qualities got reversed in India).
Let us not, therefore, jump into racial issues.
To continue and revise with more evidence.