The only military caste of
Kerala. They are Vratya Kshatriyas with descent from Nagavansh (The lineage of Nāgas mentioned in Puranas).
They were matrilineal by descent but patriarchal in nature.
They are the
rare carriers of U1 mtDNA haplogroup in
India.
Most kingdoms in Kerala which popped up after Cheras, were created by Nairs.