Meenachil Karthas (also known as Njavakkatt Karthas) were members of an Illathu Nair aristocratic clan, which ruled the small kingdom of Meenachil from 15th century AD until 1754. Unlike the other aristocratic Nair factions of North and Central Travancore who are descended from the Nāgas, the Meenachil Karthas were of Aryan origin.
Meenachil Kartha Wikipedia
The Meenachil Karthas were originally Rajputs belonging to royal lineage who migrated to Madurai in the 14th century (the reason for their exodus or their roots in Rajasthan is given as some family disputes & inter family quarrels). They settled in Madurai (which was a great cultural center and capital city during that time). Later they migrated to Kerala (the reason for which is stated as outbreak of an epidemic in Madurai) and settled in this place "Meenachil" which was named after "Meenakshi" of Madurai. Their capital was named Mevada (after Mewar).
In Kerala, they were gradually assimilated into the Illathu Nair caste, which was the major aristocratic caste in Travancore region. As they amassed power, Samanthan status as well as the aristocratic title of "Kartha" (meaning Lord in Malayalam) were bestowed upon them. But they retained their original surname "Simhar" (variant of Singh) and their culture remained markedly different from other local ruling clans. Most famous of the rulers were Veera Kerala Damodara Simhar, under whose reign, the principality achieved maximum glory.
Although like the other Illathu Nairs they were pure vegetarians, the Vaishnav tilak on the forehead distinguished them from the other clans. Also, their family deity was Bhavai instead of Bhadrakali.
The rise of Marthanda Varma of Venad, the nephew of Raja Rama Varma spelled trouble for the Nair ruling clans all over Travancore. Marthanda Varma was able to seize power after killing Raman Thampi and Padmanabhan Thampi, who were the sons of Raja Rama Varma (with Princess Abhirami, a Rajput from Kosala). Marthanda Varma and his trusted Iyer Dalawa Ramayyan started conquering the Nair kingdoms of Central and Northern Travancore one by one during the 18th century and the members of the Meenachil ruling clan were not able to avert the impending disaster. After breaking the backbone of the Southern Travancore Nair aristocracy by exterminating the most powerful clans such as the Ettuveedans and the members of Venad royal family who identified most strongly with the Illathu Nair nobility (the Thampis), Marthanda Varma under the influence of his Iyer mentor wreaked havoc on smaller Nair principalities such as Thekkumkoor, Vadakkumkoor, Kayamkulam.etc., ably supported by his Tamil allies. Many of the ruling Nair dynasties were exterminated within a few days without any trace.
Marthanda Varma's forces invaded Meenachil on 1754, and the ruler of the principality committed suicide. Almost all the members of the royal family were either killed in the battle or executed, while a handful (almost all of them women) were able to escape and take refuge under the Zamorin. At the time of Hyder Ali's invasion of Malabar during 1766, only two young females were alive within the clan. Dharma Raja granted them asylum from the Islamic forces of Hyder Ali and resettled them in Mevada.