User blog:CoyoteDork/S5B

"Much like previous seasons, the second half of the season will contain a different arc from the first half. How would the producers describe the second half of the season? “Hell,” Kitsis deadpans."

This pretty much confirms Hades for Season 5B...and I am also going to assume someone will die and their soul will end up in the Underworld. Perhaps this could also introduce Facilier and address how Phillip got his soul back.