Board Thread:Spoilers!/@comment-5679696-20160105012758/@comment-27603417-20160105044723

I like #3 as well, but that would be so strange; I think they'll go for #1, which is more reasonable. The Underworld is best if it's each character's personal hell.

However, could it be that a person's perspective of "Underworld" is the place where their remains is. For example, we might see Henry Sr. in Underbrooke because his body is in Storybrooke (or is he only in flashbacks?) Maybe, Milah's bones were transported by the curse(s) too, so that would validate her existence in Underbrooke.