Bane started the rule of two. After him, there could only be two Sith Lords.
One to embody power, the other to crave it.
I think this was meant to strengthen the Sith line. However, it doesn't neccesarily make the Order stronger as it went along; it made one sith more insidious, evil, manipulative and "effective" than the last. By the end we have Palpatine, the most evil, manipulative, insidious and "effective" one in Bane's Order. He was the planned revenge of the Sith.
That's possible... But remember, at some times the Force was greater in the Dark Side than other times. The Dark Side is corruption of the Force, not a flow of energy that Bane's Order had pure dibs on; the force breeds life and energy, but energy and life breeds the force as well (Yoda).
The Ancient Sith were immensely powerful and numerous, and in my theory, their existance caused a nexus of Dark Side energy in the galaxy. Although they had to "share" the power, it's fair to assume they had a larger source of energy.
For example, by the OT we have two Sith who have the force to themselves. However, there are only two beings corrupting the force in the first place.
Originally posted by jollyjim311
Also, it allowed the two to have more command of the darkside. When there were a lot of Sith/Dark Jedi, the darkside was "Spread too Thin" and made the Sith less powerful, due to the sharing of power.
Originally posted by Darth Avis
it was written in the comic...
Really Jedi vs Sith is full of bullshit.
Problem here is that GL and the EU conflict somewhat.
GL has commented that the traiditon of there being only two Sith has gone on for thousands of years.
The EU makes it out to be only a thousand years ago, and even more confusingly often makes it out to be a secret, so it is unclear how the Jedi knew it in TPM.
I think the EU is in trouble there, continuity wise. George Lucas' comments make it clear that when Jedi fought Sith at anything other than the very first time it happened, there were just two of them.
I think Yoda knowing about the rule of two was just a plot hole on lucas's part. There was no way for Yoda to know about it. Also the rule of two was created so the sith could remain hidden. I do however think the it did eventualy weaken the sith. Palpatine was not even that powerful. He had to use Kyber Crystals just to be as strong as we saw. About the only Sith Lords that ever impressed me from the movies was Vader and Maul. Maul was just realy gifted in the force he was just very good at hand to hand combat. Not to mention he had been training with Palpatine for quite a while. I do not think Palpatine had planned on Maul getting killed. However once realizing Anakin's potential he realy changed his plans to include him. I will say this though. Palpatine was one of the smartest sith but his plan did have some flaws. His mistake was taking over as Supreme Chanceller. He should have put in some weak minded pawn. Everyone knows the way to take out a group is to take out the leader. So if that leader died he could have just replaced him with someone else and Palapatine rules behind the scenes. Also I think the jedi in the prequal time were weaker then the order was in the old days. Just look at how Palpatine fooled them so easily.
Well if the Jedi knew about the Rule of Two all they would have to do is find the Sith kill the two of them and be done with it. I think that them not knowing it would give them a fear that the sith might come back or even still be out there if they killed of two of them but as we all need to remember there is a difference between Dark Jedi and the Sith.