Name?
In mid-August 2013, MMO Champion reported that Blizzard trademarked the name "The Dark Below" which could be the name of the new expansion (MMO Champion has a pretty good track record on these things).[2] "The Dark Below" is a region of demons and other evil creatures according to the The RPG Icon 16x36 RPG's Manual of Monsters, [3] which gives hope to those who wanted or speculated a return of the Burning Legion.
Likely eliminating Diablo 3 from the running for using the name "The Dark Below", Blizzard launched a minimalist teaser site for Diablo 3 called "Reaper of Souls",[4] and the background image is called d3x_teaser-en-us.jpg.
Name debunked?
It looks like the evidence of "The Dark Below" trademark by Blizzard was not so strong. As, according to MMO Champion, applications don't apparently have to be done by the actual applicant. So, there is a good possibility Blizzard had nothing to do with the application. MMO Champion is declaring this a hoax.[5]
Or not?
Reddit has now muddied the waters by giving evidence that someone in Europe is attempting to trademark "The Dark Below" as Blizzard.[6] If Europe's system is like the US and the registrant is not confirmed until the application is accepted, we'll have to wait and see if this is for real in Europe also. Comparing the status of the EU application shows that as of 20-Aug-2013 it is merely "Filed"[7] and not yet "Registered".[8]
Pentagram
The Old Gods pentagram
http://images4.wikia.nocookie.net/__...-Pentagram.jpg
There is a fan based theory that the Old Gods exist in some sort of pentagram, as shown in the image opposite.
At the top of the pentagram is Yogg-Saron, following clockwise is a potential Old God that lives under the Tirisfal Glades, however this was commented on by Blizzard, saying there is something 'incredibly unsettling' but not an Old God. the same evil source which forced the High Elves to find a new land, how. The next Old God (following clockwise again) isn't directly hinted at, but it would help complete the pentagram. Next is C'thun at the bottom of Kalimdor. In Northern Kalimdor is the Master's Glaive.
With Y'shaarj being added in Mists of Pandaria, the embodiment of the Sha the Pentagram is somewhat broken. So now the Pentagram may be a Hexagram.
One of the most called for expansions is the return of the Burning Legion [9], as Kil'Jaeden and Sargeras still need to be defeated, along with other bosses. Chris Metzen said in a conference that in the next expansion we will need
Turalyon's and Alleria Windrunner's help and that the possibility of Illidan Stormrage returning will be large. He said he loves a "good redemption story."
One of the most hinted at expansion ideas is The Dark Below could be related to the underwater realm of Queen Azshara and the Old God, N'Zoth. The story of Ozumat has yet to be finished as well. There will be likely an ancient city involved called Ny'alotha mentioned by the Puzzle Box of Yogg-Saron and hinted by more unique creatures. The box also refers to the ocean more in its whispers and refers to sleep, also including the Emerald Dream.
Another called for expansion is an exploration of the Emerald Dream,[9] and with it the Emerald Nightmare, such an expansion would probably also include Old Gods.