Literature starting with poetry in Sanskrit was mainly devotional in tone and tenor, and so does the Assamese version.
Since all the adaptations are being rooted in Sanskrit, making no contrary to this Assamese literature (poetry) was at the devotional tone and tenor.
Starting with a very few adaptations, Assamese Poetry were of the devotional type in the very beginning.
Sankardev (1449–1568), the initiator of the Bhakti movement, started the process of translating and adapting different books and episodes of Bhagavat-Purana by rendering more than seven books (SKANDHA) and composed a few kāvyas basing on that.
(There is still confusing to call them poems since they were sung with musical instruments like KHOL and TAAL).