(Sources: Storm King’s Thunder, page 110, Princes of the Apocalypse)

The Sumber Hills are where the Temple of the Elements are located. This is the multi-leveled dungeon in Princes of the Apocalypse, with a more cohesive history. It was originally built by an ancient dwarven empire, where they established a stable connection to the Elemental Planes, so that they can imbue their smithing with elemental energies. Ever since its rediscovery people far and wide were looking for ways to harness this power.

Of course, the Elemental Cults want to take this temple and use it to return Faerun into “a more natural state.” Figures, someone discovers a new form of energy, someone else is overcome with a need to make a bomb out of it. Something for the people on the table to think about while dealing with the prophets.

Only one of them were dealt with in my original run of Princes of the Apocalypse. I know that they’ll be back.