User blog comment:IamJakuhoRaikoben/Chapter 457: Naked Battle, Review./@comment-5894890-20151019150810/@comment-86.66.207.124-20151019151934

another theory : Layla was a spriggan, she was evil and killed Brandish Family. An event occured, maybe due to END or Igneel and Layla resigned from the S12 and quit Alvarez. Later Brandish after a training fueled with hatred take Layla's spot among the S12