In Tamilnadu one shall come across Sivacharyas in Siva Temples. They are also called Gurukkal or Kurukkal .They are entrusted with Pooja in Siva Temples.They are generally well versed in Agama Shastra, which is a prerequisite for becoming a poojari in Temples.These Sivacharyas are Brahmins.I have, in my travels come across many Sivacharyas.They perform all the Karmanushtanas of a Brahmin.Though many Brahmins in South may not say it openly, I know that the Sivacharyas are not considered Brahmins. I have tried explaining that Sivacharyas are Brahmins, people did not accept my views and most Brahmins down South avoid having matrimonial alliances with Sivacharyas.
I have been searching for evidence about the origin/ history of Sivacharyas.The reason is that Sivacharyas have a tendency to lean more towards Tamil Saiva Siddhandha practices, though they are Vaidikas,that is they follow Vedas and worship Agni.Vaidikas,(I am, at least by disposition,is a Vaidika,) ,though are quite conversant with Saiva Siddhandha, lean more on Vedas.If there is a conflict between Vedas and Saiva Siddhandha,sometimes philosophical points differ ( in essence there is no difference but exposition of the Principles make the novice think there is a difference), Vaidikas take Vedas as ultimate Authority and Sivacharyas take Saiva Siddhandha as final.(This point is debatable.)
This has made me look for the history of Sivacharyas.There have been migrations to Dravida Desa from Aryavartha,North of Vindhyas .Brahmins migrated from Dwaraka and Agastya and Parashuram too settled Brahmins in South and these Brahmins intermingled with Brahmins of South and were assimilated. Sivacharyas stand out .
Sivacharyas were brought from Bengal by Rajendra Chola son of Rajaraja Chola,after his expedition to North India. He defeated most kings of North India and brought Ganga Water and performed Abhishek for Siva at Thiruloki, Tamil Nadu.
Rajendra Chola’s expedition to North India was between 1019 and 1024 AD.
While returning to his kingdom in South, Rajendra Chola brought Bengali Brahmins and these are the ancestors of Sivacharyas of today.
The Siddhantasaravali of Trilocana Sivacharya claims that a large number of Saivite Brahmins from Bengal were taken to the Chola country where they were granted lands by Rajendra Chola I. They, eventually, settled down in Kanchipuram and the Cauvery Delta forming the Sivacharya community.https://en.m.wikipedia.org/wiki/Chola_expedition_to_North_India#Sastri.