User blog comment:IamJakuhoRaikoben/Chapter 457: Naked Battle, Review./@comment-5894890-20151019150810/@comment-26389992-20151019151523

Possibilites I've seen:
 * Layla was a Spriggan and you can basically piece that one together
 * Layla and Brandish's mother were close and something happened between them which carried over to Brandish (this is what I'm thinking)
 * Her being related to Karen, celestial spirts, blah blah... tired of family relations that make no sense but this is the wildcard