Sith/Dark Jedi in Jedi temple possible

Question

Would it be possible for Jedi to live and to work in the Jedi Temple, but be completely on the Dark Side (for example, for studying purposes)? I mean, could they help to understand each other or does being a Sith/Dark Jedi equate to I have to kill all Jedi and to rule over the galaxy?

If not, then why are there no Dark Force users in the Jedi temple (or did I just overlook them)?

EDIT: For explanation: I meant a situation where the Jedi know that there is a Dark side user in their temple, and they work together, not that the Dark Side user is hiding his dark side.

Answer 1

Wow, no. Absolutely not.

The Sith

The Sith and the Jedi are mortal enemies whose goals are completely dissimilar. Aside from using the Force they share no common aims or philosophy and have battled against each other across the galaxy.

There are some (low canon) instances where Sith and Jedi have worked together against a common foe but bluntly, the Jedi are trained to kill Sith on sight and one of the Sith's primary long-term goals is the complete destruction of the Jedi Order.

Dark Force users

Obviously, it's perfectly possible to be an adherent of the "Dark Side of the Force" without being a Sith but it's very hard to imagine that the Jedi would accept a known Dark Force user in their midst given that their strength flows from....

anger, rage, hatred, fear [and] aggression

All of which are totally inimicable to the Jedi code.

Answer 2

The Jedi would most likely never knowingly allow somebody to train in the Dark Side within their temple. This answer is mostly expanding on Richard's point that the Jedi and Sith have competing values.

Here are Mace Windu's thoughts on the Clone Wars and the Dark Side:

Spoilers for Shatterpoint

The Seperatists are not the true enemies of the Jedi. They are enemies of the Republic. It is the Republic which will stand or fall in the battles of the Clone War. Even the reborn Sith are not our enemy. Not really. Our enemy is power mistaken for justice. Our enemy is the desperation that justifies atrocity. The Jedi's true enemy is the jungle. Our enemy is the darkness itself: the strangling cloud of fear and despair and anguish that this war brings with it.

Note that the jungle Windu is referring to was on a planet that was steeped in the Dark Side because of lots of war and killing. In this jungle, the Dark Side drove Windu's former padawan, Depa Billaba insane and she fell from the light. In short, the Jedi's true enemy is the Dark Side itself.

Here are the views of Darth Plagueis:

Spoilers from Plagueis

For while toppling the Jedi Order and the Republic was essential to the task of restoring order to the galaxy, that goal belonged to the realm of the ordinary--to the world that was nothing more than a byproduct of the eternal struggle between the light and dark forces, both of which were beyond any concepts of good or evil. The greater goal of the Sith involved toppling the Force itself, and becoming the embodiment of the galaxy's animating principle.

Further down (talking about ruling the galaxy and other stuff):

But not until the singular flame of the light side was extinguished from the galaxy. Not until the Jedi Order was stamped out.

So as you can see, if Darth Plagueis tried to waltz into the Jedi Temple and declare that he wanted to study the Dark Side there, I think Mace and the other Jedi would have a problem with that.

What about the Dark Jedi?

Let's take a look at a few prominent Dark Jedi:

Asajj Ventress, Aurra Sing, Set Harth, and Depa Billaba were all Jedi that fell to the Dark Side. Ventress and Sing were responsible for the deaths of many Jedi. Harth was responsible for the deaths of a couple civilians. Depa was charged with crimes against civilization because of her actions on Haruun Kal.

Suffice to say, it is improbable that the Jedi would allow any of them to study at the Temple at all.

There are many other Dark Side practitioner's as well, but they most likely wouldn't get the nod either.

Let's recap:

1. Darksiders tend to not like the Jedi.
2. The Dark Side can corrupt Jedi.
3. The use of the Dark Side is generally incompatible with Jedi beliefs.
4. I highly doubt Coruscant and Korriban had a foreign-exchange program for students.

Answer 3

It would be possible, but highly difficult, and a Dark Jedi/ Sith would already have to be quite knowledgeable in the Force in order to do so. Anakin Skywalker was able to disguise his Dark Side tendencies at the Temple, as was Jorus C'Baoth, and Palpatine was routinely meeting with Jedi as part of his duties as Chancellor. Kyp Durron had trouble disguising his Dark Side tendencies from Luke Skywalker, and Luke was nowhere near as knowledgeable or as powerful as the Jedi of the Old Republic.

EDIT:

In response to the OP's edit, I must point out that no, this is not possible. Jedi and Dark Jedi don't work side-by-side, except under extreme duress, such as the Abeloth incident.

Answer 4

No, as answered in some depth already.

The Jedi and Sith are mortal enemies. The Jedi thinks that the Sith are the worst thing in the galaxy. Even Jedi Master Mace Windu is about to kill Palpatine because he thinks a Sith Lord is too dangerous to be kept alive and stand trial, even when Palpatine is unarmed and helpless (even if he isn't helpless, Windu thinks he is and that is what matters).

Revan, Jedi turning to the Dark Side before going back to the light, is basically shunned by the Jedi in the novel 'Revan'.

In the Bane trilogy:

When the Jedi found out that Bane is seriously injured, they send a Jedi strike team to kill him. Another character in the trilogy, Set Harth, is a Dark Jedi who has been hiding from the Jedi since turning his back on them. This indicates that they would punish him in some way, if they found him, even though he doesn't even pose a direct threat to them.

The Bane trilogy also mentions Sith Holocrons, which the Jedi searches for, in order to hide them in their restricted section of the Jedi Archives. And

when Darth Zannah does research in the Archives in disguise, she has to suppress her Dark Side aura so that the Jedi doesn't find her. She is not out to harm anyone, she is just in the public section doing research, but as soon as the Jedi find out, they send out a team to intercept her.

Those short examples, as well as the previous answers, makes me believe that there is no chance that the Jedi would let Dark Force-users freely roam the Jedi Temple.

Answer 5

Yes (Ummm…)

At least one confirmed occasion, as seen in Star Wars: Episode III - Revenge of the Sith, Palpatine visited the Jedi Temple.

This occurs after Order 66, “all” of the Jedi have been wiped out after Mace Windu’s posse’s coup d’etat attempt, and Anakin Skywalker cleanses the Jedi temple on Coruscant of any anti-Emperor insurrectionists.

In the film, Obi-Wan and Yoda’s view a holorecording of Darth Vader kneeing before the Emperor.

Matthew Stover’s novelization holds that Darth Sidious traveled to the Temple in person. This in-person visit is supported by additional sources. The security recordings Kenobi and Yoda were looking at were of events going on inside the Jedi Temple training hall. The book Star Wars Chronicles: The Prequels states outright that these recordings were in part used to help in lightsaber training (and remember that much of the recording was of Anakin killing the lightsaber trainer Cin Drallig and his students).

Additionally the “Casualty Report: Order 66” article in Star Wars Insider also states that the actions were recorded on Jedi Temple holocamera TR4-121.

We can conclude the camera continued to record Anakin after he finished killing Drallig and the trainees, and then Sidious steps into view and gives him the old "You have done well" routine. As confirmed at least in the novelization, the visit by the Dark Lord of the Sith occurs in person.

Whether any Jedi would be happy to work with Sidious to share ideas on religion or galactic governance, however, is unknown because Sidious orchestrated their complete and total demise, ensuring anyone still inside the temple was murdered. The Jedi at this time would probably not be bending over backwards to put Palpatine in charge of the youngling training committee, for example. Rather than be inspired to share diverse philosophy of the Sith, whatever remaining Jedi might be inclined to go into hiding, and conspire to exploit the next generation of prospective Jedi offspring to extra-judicially assassinate the dual Empire’s head of state and Sith religious leader if an opportune chance presents itself like a visit to a large-scale Homeland Security infrastructure construction project with the entirety of his Sith congregation.

However, this lack of any Jedi in the Temple to receive Darth Sidious on his visit is not any failure of the Sith to visit the temple, however, but rather highlights the ability of the Jedi to anticipate how such visits to their temple by the Sith might occur. The Sith likely would always be interested in visiting any Jedi Temple they can get their hands on. The Jedi simply didn’t have the right conditions in place to make the Sith’s visit the most positive experience it might have been.