That’s really interesting. I actually just read Dark Empire and I’m on Dark Empire 2 right now. I still question that internal logic though because the Emperor was clearly Vader’s master, and the Dark Lord of the Sith wasn’t ever subordinate to anyone else in TOTJ, other than ghosts of former Dark Lords like Marka Ragnos.
I’m trying to think of a justification for this inconsistency and I’m coming up blank.
I like to entertain the idea that Anakin joined the Sith specifically to gain the power to defeat Palpatine. But he overestimated his own abilities, confronted Palpatine half-cocked, had his ass handed to him, and was forced to join him or die.