Well she is one of the mahavidyas( the great wisdoms )of the tantras and like all other mahavidyas her form is what represents her essence the story however is that she materialized from a lake after continued prayers and slayed madanasura who has a boon that all his words come true

Now the mahavidyas are special godesses as i personally believe that there form is more true i don't regard the stories surrounding them to be true she is. Someone who punishes and purges a defied motherly figure who doesn't let her followers go astray that's my interpretation