Devengas' are a community from South India

South India

South India is the area encompassing India's states of Andhra Pradesh, Karnataka, Kerala and Tamil Nadu as well as the union territories of Lakshadweep and Pondicherry, occupying 19.31% of India's area...

 that traditionally followed the occupation of weaving. Some Devangas consider themselves to be Brahmins, while most others classify themselves as Vaishyas.
The caste traces its origins to the sage Devala Maharishi. Communities following this caste are mostly spread in southern Indian states of Karnataka, Andhra Pradesh and Tamil Nadu. Much is not known about its history.The Devanga purana

Devanga Purana

The Devanga puranam describes the Devanga cult, their goddess, rituals and customs. It is included in the Brahmanda Purana; originally written in Sanskrit, it has been translated into Telugu, Tamil and Kannada.-Summary of Devanga Purana:...

throws light on the early origins of this caste.

Devangas originally are people who migrated from northern karnataka.