Shyamala Devi is not just a folklore.She is mentioned in the Brahmanda Purana.How she was created by Lalita Parameswari is mentioned in the Lalitodhvaba episode(Manifestation of Lalita) of the Brahmanda Purana.
Quoting from this page:
At the end of the Homa, Lalita Devi came out of the Chidagni Homa
Kunda, seated on a special chariot called “Chakra Raja ...
According to Jahnava Nitai Das of Bhaktivedanta Ashram
Shyamala Devi is the form of Durga Devi who assists Lord Krishna in interacting with the material world during His incarnation
(as Shyama). For every incarnation of Krishna or Narayana there is a
form of Durga that assists Him to interact with the material energy.
Narayana is nirguna, He does ...
ShyAmalA is one of the chief Tantric goddesses in the Sri vidya krama. She is also one of the mahA-vidyAs of the shakta tradition as she is the mahAvidyA mAtangi herself.
She is known with many names like Raja ShyAmalA, Raja mAtangi, matangi, mantriNi etc. All these aspects are similar to goddess Sarasvati. In other words, these are tantric forms of ...
From the Varaha Purana chapter which describes how the Ashta Matrikas manifested during the extermination of the demon Andhaka.
The entire Universe was upset by the wickedness and glaring
transgression of morals by the uninterrupted evils displayed by Demon
Andhakasura [Siva Purana states that Devi Parvati was playful with
Maha Deva by closing His ...
Raja Shyamala Devi or Raja Matangi mata is a goddess in Sri Vidya Upasana. A higher expertise can be achieved by her upasana. She is also mentioned in the Lalita Sahasranama. She is also a source of education and knowledge like Saraswati Devi.