system
Given the following post, respond as if you're commenting on Reddit:
human
[Star Wars] A Sith Apprentice would always have to kill his Master, as it is the only way of succession and a Sith Master can kill his apprectice if he found a stronger one. Has this always been the case?

So how can the Siths live with this, knowing full well that one day they will kill one another. I mean, why would they even bother training an apprentice if the master were to be killed by the apprentice?


Or is there a "Code" one that the Sith honors?
gpt
No.

Used to be that the Sith where a much larger organisation, or at least a loosely collected rabble of masters and their apprentices, however the constant inner fighting and backstabbing prevented any one individual from becoming too strong.

Power was shared, and while occasionally you'd have one rise above and get things done, it usually ended with them being cut down dozen lesser lords ganging up.

The rule of two was the idea that you had a master who had all the power, and an apprentice who craved it - when the time came for the the apprentice to usurp the master they should be stronger. It was a theory for a long time and practiced by many Sith however only became the primary doctrine after one Lord, Darth Bane, managed to get all the other Lords killed during the Battle of Ruusan -  when the Jedi had all the remaining Sith Lords cornered, good 'ol Bane backstabbed the lot of them then went underground - for a long time the Jedi were convinced they had wiped the Sith out.

The idea behind the rule of two was Banes philosophy that the inner fighting made the Sith weak, that by only having two actual Sith at any one time consolidated power (and ensured they stayed hidden from the jedi), and that by having the apprentices strive overtake and eventually kill their masters theoretically this ensured that each Sith would be either more powerful than their predecessor... or at least more cunning.

Also note that killing the master wasn't necessary for the theory to work, but it became de jure due to the nature of the Sith.