Something I just realized, that others may have already realized.
Back in 1999, when The Phantom Menace came out, Obi-Wan singlehandedly killed a Sith Lord Star Wars canon by slicing Darth Maul in two.
Then, in 2012, Darth Maul returned in The Clone Wars and managed to survive until the show was cancelled in 2013.
Therefore, Kenobi never truly killed a Sith Lord. The only Jedi to ever actually kill a Sith Lord? Anakin Skywalker.
- Anakin killed Count Dooku
- Anakin killed Palpatine, sacrificing himself in the process.
Every other Sith Lord was killed by another Sith, ostensibly during their succession from apprentice to master over the course of the millenia, per the Rule of Two (except for Vader, who was killed by his master).
With the return of Darth Maul to Star Wars Rebels, I wonder if that will remain true. Will Maul die by Vader's hand?