The important thing to remember is just how big the galaxy is, and just how many sentient beings are in it. Most people would probably know something about Darth Vader, but if you told them that he was Anakin Skywalker, they would probably say "who's that".

We actually played with this a bit in one of our last campaigns. The setting was low level Coruscant just after the Disband of the senate. I played a Bothan PI, and a reoccurring gag was that my PI was a conspiracy theorist, and had all these wild theories about the Emperor being a Wizard and orchestrating a secret war with the sole intent of destroying the Jedi, and that Darth Vader was actually the fallen Jedi Obi Wan Kenobi, and so on-

The GM played with it too. A turning point in the campaign was when the Imps started a crackdown because 'Rebels' destroyed a 'Mining Station' killing thousands of loyal Imperials. Yep - Death Star.

Good times.

We actually played with this a bit in one of our last campaigns. The setting was low level Coruscant just after the Disband of the senate. I played a Bothan PI, and a reoccurring gag was that my PI was a conspiracy theorist, and had all these wild theories about the Emperor being a Wizard and orchestrating a secret war with the sole intent of destroying the Jedi, and that Darth Vader was actually the fallen Jedi Obi Wan Kenobi, and so on-

The GM played with it too. A turning point in the campaign was when the Imps started a crackdown because 'Rebels' destroyed a 'Mining Station' killing thousands of loyal Imperials. Yep - Death Star.

Good times.

Okay. That sounds awesome. I now want to play a similar character and make him a propagandist from Desperate Allies.

Also a lot of former titles are now actual names today. How many people have names like Duke, Monk, Priest etc? Lots so are you going to assume that Darth Vader is a member of an Force society that has been extinct for a thousand years or has just picked up the name because his parents thought it was interesting and didn't know the history?

You make good points. There's certainly scope for misinformation being spread. It was a counter-measure I didn't consider. If judiciously applied (you don't want the cure to be worse than the disease), that could be a viable way of dealing with things. "Darth is a common name amongst the people of Mustafa" for example.

But the above made me laugh. It's such a delightful idea and logical too:

"But we've been searching for you for months because we thought you were a surviving Jedi who could help us!"

"Say what?"

"But they called you Padawan."

"Uh, that's my name. My parents named me after a Shak-Ti that saved their lives in the Clone Wars. Her name was Padawan Tano. I'm Padawan Tano Bonteri."

"..."

Or imagine how many Obi-Wans and Anakins are out there after all those wartime heroics! Must make rooting out the real Obi-Wan pretty tricky.

The important thing to remember is just how big the galaxy is, and just how many sentient beings are in it. Most people would probably know something about Darth Vader, but if you told them that he was Anakin Skywalker, they would probably say "who's that".

I'd say far more the other way around. Anakin was not merely a general in the Clone Wars, but a particularly famous one involved in many critical victories and fought on the front lines alongside his soldiers frequently in a highly visible fashion. He had a reputation amongst the clones beyond any other Jedi. He also killed Count Dooku and rescued Palpatine himself during the decisive battle over Coruscant. The Clone Wars were what... twenty years ago? Plenty of people would still be alive and well who remember these events first hand and many more would have heard or read the stories.

Whereas Vader - some sinister high-ranking aide to the Emperor mainly interacted with by other high-ranking members of the Empire. Certainly known of - Princess Leia knew of him ("only you could be so bold") when he stormed her ship and the Rebels would have a good idea of his existence having come up against him. But the common people and rank and file would have no especial reason to give him thought, I suspect.

I think the galaxy is a big place. It's risky to talk about it as if it were a single society. Whilst obviously Star Wars is absurdly simplistic and often paints it that way, there would probably be whole sectors where the Sith were fairly well known - planets that endured long periods under their rule for example - whilst in other areas the name probably wouldn't even be recognised.

Maybe there's a planet with a dark history and the people may not know every detail of the Sith but they'll notice that they had a series of tyrants called Darth Baddius, Darth Sinisterus, Darth Gropeus, etc. It may not be that exactly, but there will be enough history with the Sith that details like this are familiar to them.

Whilst of course there would be planets more recently settled, less involved or simply less interested where even "Sith" doesn't ring any bells. This may or may not seem obvious but my real point is about to come. It only partly matters how few people know this stuff if the exposure of its return is widespread. You know how once one person spots a continuity error in a movie or points out a flaw in some news story, everybody hears about it. Even if 99.5% of people in the galaxy don't know much more about the Sith that we do about the Pharaohs, you can bet the moment someone called Darth Vader hit the Holonews, every historian in every university and every armchair antiquarian would be leaping to their feet to talk the ears off anyone who would listen. And it's not just titles, there are other giveaways like inquisitors who use the Force but clearly are not Jedi. It's not proof of Sith - there's "a lot of strange things" in the galaxy to quote Han Solo. Dathomir witches and Bardotens, planets strong in the Force where odd things sometimes happen and all sorts of spooky little corners of the galaxy that people avoid. But still, it will make people think and even if they're few, their natural response will be to talk.

So the question then becomes not how little or how much people know, but to what degree information is contained. Just how secret are things like the inquisitors or Vader's "first name"? And as a counter-part to that, how much active suppression does the Empire do? I mean you can censor words and monitor communications but that can backfire badly, just ask the Lady of Sith Darth Streisand what happened when she tried to suppress knowledge of a minor incident. The Empire is an organization of billions of people. If you send out a message to your Ministry of Information to put "Darth" and "Sith" on the watch list you've just tipped your hand to millions of your own staff.

Suppression of events post-fact is viable. Something happened on Lothal we don't want people know about? Blacklist it from the news organizations and monitor the independents and pirate stations for mentions. It's viable because the tipping your hand (some people have to know in order to watch and suppress it) is set against something worse (uncontrolled spread). Pre-fact censorship is a lot less viable because you're tipping your hand for something that isn't actually a problem right now.

Where this leads us is that censorship on things like Inquisitors and Sith nomenclature has to be done at a local level as needed. So I think things like Vader's Sith title are for between those "in the know". Palpatine, the Inquisitors... I'm thinking there is a structure within the Empire, an inner circle - people who have official ranks within it, say an Inquisitor is officially a captain in the ISB seconded to other branches of the Imperial power structure as needed but really the ranks are bestowed as a tool to suit their position in the Sith-aware inner structure. I would have no doubt that plenty of people within the Empire know there are wheels within wheels, but it's generally a hushed voice thing kept within the organization. The ISB agent in Rebels doesn't necessarily know the Inquisitor is Force-sensitive (although he might), but he's certainly smart enough to know who he takes orders from and that it's more than just the standard hierarchy. The high-ranking officers on the Death Star aren't completely freaked when Vader who they know to be a sorcerer chokes someone with a gesture - they're all powerful men and aren't cowed by it (though it no doubt terrifies lesser officers); and they undoubtedly talk about it amongst themselves and confidants - Vader is probably surrounded by dark rumours which is how he likes it. But they wont be talking to outsiders about it much. I imagine the Empire is not an environment in which gossips find themselves popular - too much fear and distrust to like someone around who you know likes to blab.

The Emperor is sitting on a powder keg. Detailed knowledge of the Sith is unlikely to be commonplace, but it must be relatively easily obtainable by huge numbers. I'm not aware that the Star Wars universe had a Dark Ages between Sith empires and the current era (the Dark Ages are named that because so little was written during that time period that it was 'dark' to historians). So there must be innumerable sources. So I think the Emperor must be keeping the powder very damp and avoiding too many sparks. Inquisitors are dark rumours, Sith titles are for between conspirators, it's okay for the Emperor's attack dog to be a known sorcerer but it must not appear that the Emperor is.

It's not about historical knowledge, it's about making sure nobody joins the dots.

I think this is one of the things Star Wars: A New Dawn did very well... showcasing what was known and being found out by the eyes and ears of the security forces, and ultimately the Empire. Some characters had a lot of knowledge about the worlds around them (Kanan / Caleb) versus a lot of the miners that really only knew about their world and the moon. We see this a lot in our own world. People that are from a small town that have never been outside of their own county, are going to be less interested in and have little knowledge (generally) of historical or political events of distant times or distant planets. Someone that grew up traveling as a kid with parents that could afford to go places is going to be more curious and exposed to a lot of different thoughts and civilizations. Obviously, there are going to be exceptions to both of those (the poor kid that lived his whole life exploring others through the local library and finally gets a chance when his parents are murdered and he is sought be the authorities) but the patterns are there. Some might be hard wired differently. Even on remote Tattoine a farm boy dreamed of joining an Academy of pilots despite everything his "parents" tried to prevent it.

Back to the Viking example:

If the government makes me their chief enforcer, I affect a Type X sword and spangenhelm, and everybody calls me, "Jarl Vigil," it won't take long before many people believe - rightly or wrongly - that I and the government must think I'm some sort of Viking.

Same thing if the government starts referring to me as "Khan Vigil", "Archon Vigil", "Consul Vigil", "Caesar (or Kaiser or Tsar) Vigil", &c.

As mentioned, it is much easier for the Chinese government to suppress knowledge of what happened at Tiananmen Square in 1989 than what happened, say, to the Song dynasty in the 13th Century (they were conquered by the Mongols).

Similarly, it will be much easier for the Empire to control and suppress knowledge of what happened during the closing days of the Clone Wars (and into the Galactic Civil War) than to do likewise with what happened during the last of the wars against the Sith.