Deletion of Fifth wall

Comment: I am conflicted on this. It clearly is not the "fourth wall," which has had its own problems with original research examples added by Wikipedia editors. Where is a |reliable source describing a "fifth wall" as what separates an actor's portrayals of different characters in different fictional universes? Yet it is a meaningful concept, and I would be surprised if no reliable source ever had reviews or criticism about it. Perhaps a different term is used
Stance: comment
Cited policy: Wikipedia:Reliable sources (WP:RS)