Some sites say its not, others like IGN say they have confirmed it is, but most, including the official website, remain vague on the matter, and the true identity of the Sith Emperor remains uncertain. There was some discussion over a Video Interview where a producer for BioWare mentions that when Raven & Malak went into deep space they found the Sith Emperor, the same Sith Emperor from the Great Hyperspace War who was thought to be killed by the Jedi. On the TOR website's page on the Sith Empire it mentions this: "Dark Lord of the Sith Naga Sadow led his armies in an aggressive campaign to destroy the Galactic Republic. Though the Sith were successful at first, the Jedi Order rallied back to defeat their dark counterparts, systematically destroying the Sith civilization on Korriban. Unbeknownst to the Jedi however, the last Emperor of the Sith managed to escape the carnage and fled into Deep Space.
" The last reigning Dark Lord (Emperor) during the GHW was Naga Sadow. He was thought to be killed by the Jedi and he did flee into the outerrim, which at that time wasn't as explored and would be consider Deep Space, with the hopes of rebuilding his Empire. The timeline entry about the GHW mentions that the same Sith Empire they thought they destroyed is the same one that has come to seek revenge. However some sources say his spirt was killed by Freedon Nadd. Other sources say he encased himself in a suspended animation chamber where he remained in a coma-like trance for centuries, thus he would not have been a spirt when Freedon Nadd found him. Not matter which source you look at their is disagreement on how & if he died.
The questions then arises that the Sith Emperor, when picture in the Star Wars: The Old Republic, Blood of the Empire
webcomic, appears to be a Humanoid. So since Naga Sadow was half Sith Species this can not be him. But wait, Naga Sadow was also a great and powerful dark side magician. Thru use of Sith Sorcery he may have used Essence Transfer to transfer his consciousness into another body, thus living behind a empty spirt that would later be discovered by Freedon Nadd. Until the game comes out or more is revealed we will never know 100% who the Sith Emperor is.
So what is your take on this? Lets stir up some friendly conversation
Personally I can't say. I am a big believer of cannon and currently it says Naga Sadow was killed and it is a different Sith Lord under Naga Sadow who took the mantle of Emperor. But I also think it would be amazing if Lord Sadow was alive and well as Emperor.
I'd almost prefer have a separate Sith Emperor, imo. Gnost-Dural's comment in the video seems to suggest that the Sith Emperor replaced Naga Sadow while Sadow was on Yavin IV.
That said, for a fellow who survived the Great Hyperspace War (5000 BBY/1347 BTC), interacted with Revan and Malak (3961 BBY/303 BTC), and then stood behind the Dark Council's actions during the Great Galactic War (ending with the Treaty of Coruscant in 3653 BBY).
Sith Emperor (assuming age 30 in the Great Hyperspace War) would have been a whopping 1077 years old when Revan and Malak visited - which is understandable as a Sith, but still staggering. When the treaty was signed, he was 1377 years old.
Even if Naga Sadow was defeated on Yavin 4 (as in: physically died), his spirit was active for a heck of a long time afterwards. It's not out of the question that he was impacting the events.
Sources: swtor.com holocron videos, Wookieepedia
I think there was a chart showing that two Sith left Korriban, Naga Sadow traveling to Yavin, the other moving into the unknown regions. Let me see if I can find the source for that.
edit: The Essential Atlas says that Shar Dakhan is the last acting Dark Lord.
edit 2: Essential Atlas does depict the retreat routes following the end of the Great Hyperspace War and it has one line tracing Sadow to Yavin and a separate one for another Sith Lord retreating into the Unknown regions (page 127, Essential Atlas). The exact quote regarding it is, "Naga Sadow flees to Yavin; other Sith flee to Thule and Vjun. One Sith Lord regroups in the Unknown Regions to plot revenge."
It would be funny if it was Revan given the cannon lightside ending.
My gut tells me that with this game there will be a totally new Sith Emperor introduced. Here is my logic, while it would be possible to install Naga Sadow or "x" other figure as the current Sith Emperor I think we may see some new lore introduced as the game roles out revealing a brand new character in this role. I am very sure we will see Naga Sadow in the game however I think that it will be revealed that there is someone much more powerful than anyone to date in the seat of supreme power.
Again, just my theory.
I think the new Sith Emperor will be um, new. But they will link him to another character or story line. He will be germane to existing EU canon.
It's been announced that the new novel for November will unveil the identity of the Sith Emperor, can't find the link but I read it somewhere.