So this is a 3 way crossover combining Merlin Supernatural and Once upon a Time. Unfortunately I was unable to categorize this as a crossover of 3 shows. So I categorized it as a Supernatural/Once Upon a Time crossover as it ties mostly to their next seasons but I have big plans for merlin in this story so I provided this link in the merlin category so merlin fans can also enjoy it the foreword explains the plot
enjoy
I know links are weird on this site sometimes if it comes out weird just look for the other instance of this title in my profile
s/11272253/1/Working-Title-s-Out-of-The-Darkness-A-3-Way-crossover-fanfic