I’ve talked about systems, now lets think about lore. This is all wild speculation!!! These are not facts!!!
The Dark Below
Blizzard has registered The Dark Below. It seems today that the next Diablo III expansion will be called Reaper of Souls, so that leaves The Dark Below to be something else. It could be Titan, it could be all sorts of things. One of the things it could be is the next World of Warcraft expansion. If Blizzard were criticized for Mists of Pandaria being too fluffy then The Dark Below sounds very different.
The Dark Below appears on the Warcraft Wiki where it says:
The demons from the Dark Below apparently exist apart from the Burning Legion who reside in the Twisting Nether. The Dark Below may be another description for the Twisting Nether, in which case these are demons of a separate faction that live within the same plane of existence. This would explain how player warlocks are able to summon demons that do not serve the legion.
It is said that only Archimonde, Kil’jaeden and Sargaras could have matched her. After failing to bring Sargeras and the The Burning Legion to Azeroth, she became a naga, along with her most trusted aides. We know she is alive. We even saw her in Cataclysm. We know she was helped to become a naga by something powerful. It makes sense that she may be working with demons once again. If she considered Sargeras, commander of the Burning Legion, her equal, she may have sought out a demonic army of her own?
Turalyon and Alleria
Where are Turalyon and Alleria? We know that when Khadgar and company returned to Outland and rocked up at Honor Hold, Turalyon and Alleria were missing. There is a hint screen that reminds us of that. Given most hint screens are tips on actually playing the game rather than lore, this seems significant. Since Turalyon and Alleria are famous for fighting demons, this would tie in with a demon themed expansion.
Races and/or classes
Theres a distinct lack of races left for obvious inclusion here. Blizzard have said they will seed races before their introduction after the Draenei so we don’t expect one to come out of nowhere. Given the above what might we see? How about Arrakkoa and Murloc! Arrakkoa live in the Realm of Shadows, which may well tie into The Dark Below as place of shadow magic and necromancy. You see this realm a few times in the game. I suspect they would join the Alliance. The murlocs on the other hand could be driven out of the deeps by Azshara. They are a much loved part of the game (they have their own plushie) and I think players would be excited to play them.
Classes – I can see two possibilities. Given the theme so far, Necromancer is possible. However, I think this is unlikely as it is too close to warlock and death knight. The other possibility is a Sentinel/Watcher type character based on Alleria’s involvement. This has been thought about for a while. A ranged dps/healer hybrid who does dps to heal along the lines of the Fistweaver and Discipline Priest might fit nicely into the game. It might also make sense for this to be a Hero class as you would be one of Alleria’s own from wherever she has been. Sentinels could be Human, Night Elf, Draenei, Blood Elf, Goblin, Troll? Maybe also Pandaren, Orc and Dwarf?
I would expect to see Nazjatar, though probably not as an underwater zone. Whereever Turalyon and Alleria are is a good opportunity for new zones. Given that Nazjatar is on Azeroth, I would suspect they are too. I would guess, therefore, they are on the Broken Isles which happen to be near Nazjatar. You could easily have a three tier world – South Islands, Underwater, The Dark Below. The Ruins of Suramar, Mak’aru (city of the Makrura lobster-men), the Gishan Caverns (a network of caverns avoided by the Naga and home to gargantuan sea monsters) and the Drowned Reaches (ghost/zombie filled ships graveyard) all sit nearby and are ripe for use. Finally, the Rift itself is the prison of the Old God N’zoth who could easily be manipulating Azshara. This suggests another zone, via the Puzzle Box of Yogg-Saron, which mentions Ny’alotha, home of the drowned god and possibly the Emerald Nightmare.
Of course its possible to spin all sorts of speculation out of these announcements. Its fun too!
The one note of caution to all these ideas that I would state is that a lot of them are driven by Cataclysm. We know that Pandaria was not the planned expansion and that something else was developed first. That could well be this. Which raises of the question of would they go back?