Board Thread:WARNING - SPOILERS AHEAD/@comment-11593970-20130706054527/@comment-101.99.136.142-20130723143157

I believe that the Darach is the mystery girl from the first episode of the season. This is strictly based on the fact that a Darach is a Druid who "went down the wrong path." So to be a Darach you have to be a Druid to begin with, and based on the way the mystery girl was acting, she seemed like a Druid.