For decades, fans have pored over the minutiae of the Star Wars franchise, with the expanded universe filling in many of the gaps that were either hinted at in the movies or referenced but never fully explored. It remains arguably the richest and densest mythology in popular culture, which is one of the main reasons why people will never turn their backs on a galaxy far, far away.
George Lucas drew his inspirations from everywhere including ancient history, mythology and the sci-fi stories he loved himself as a child, combining them into an old fashioned tale of good versus evil set against an epic intergalactic backdrop. Things might have become increasingly muddled with tales of Midichlorians and Dyads, but the core concept has always revolved around the Jedi battling against the Sith.
The various novels, comic books and video games have added new layers onto the generational saga, but one constant is that the Jedi have been Knights and the Sith have been Lords. Nobody has ever really questioned why, but once again, it boils down to the simple dichotomy of good and evil.
Not only is it because the Order are based on the Knights Templar, but the Jedi also use the moniker as they deliberately distance themselves from holding official titles of nobility, while their sole aim is to maintain peace and they’re overseen by a committee so that no one member has the power or authority to rule them all.
On the other hand, the Sith are all about seizing power, and bestowing the title of Lord establishes that there’s a single person in charge. The Sith Rule of Two establishes that only a Lord and the apprentice set to inherit the mantle can exist at the same time in Star Wars canon as well, separating the collective Jedi even further from the self-serving Sith.