In Ramayana
In the Ramayana, the term Arya can also apply to Raksasas or to Ravana. In several instances the Vanaras and Raksasas called themselves Arya. The Vaanar king Surgriva is called an Arya (Ram: 505102712) and he also speaks of his brother Vali as an Arya (Ram: 402402434). In another instance in the Ramayana Ravana regards himself and his ministers as Aryas (Ram: 600600512).
A logical explanation is that, Ravana and his ministers belonged to the noble caste (Ravana being a Brahmin) and such people were generally considered 'noble' of deed and hence called Arya (noble). Thus, while Ravana was of Arya caste (and regarded himself as such), he was not really an Arya because he was not noble of deeds. So he is widely considered by Hindus as Anarya (non-Arya).
The Ramayana describes Rama as: arya sarva samascaiva sadaiva priyadarsanah, meaning "Arya, who worked for the equality of all and was dear to everyone."
Nagas also referred to themselves as "Arya" or "noble". So they were Aryans like the vanaras of the South.
Read more about this topic: Nagavanshi