Yakshas
Main article: Yaksha Kingdom or Yaksha
The Yakshas were a kind of beings whose king, Vaisravana or Kuvera, was a worshipper of Siva. He is regarded in Hinduism as the Lord of all wealth.
According to Ramayan Kubera established or rebuilt the kingdom of Lanka (now known as Sri Lanka) and inhabited with Yaksa people. Later on Kuber's step brother Ravana (they had same father Vaishravas) took over Sri Lanka, upon their father's request Kuber moved to the region near Kailasa mountain in Himalayas.
Read more about this topic: Exotic Tribes Of Ancient India