, as their name suggests, are originally conceived of as the guardians and personifications of esoteric wisdom , namely mantras and dharanis. They were seen as embodying the mystic power contained in these sacred utterances.

During the early stages of esoteric (Vajrayana) Buddhism, many of the deities that would become known as (a term that only came into use around the late 7th-early 8th century) were mainly seen as attendants of bodhisattvas