I wonder if this refers not just to Vader, but possibly others who may have switched allegiances as well?
The inquisitors used to be Jedi so he might have met some of them before, or even fought beside them during the Clone Wars.
Ah. My hopes of seeing a reunion of Kenobi with a Dark Side Dexter Jettster at the 1950’s cafe will live on! 😃
That would be good story material to see Kenobi have to now have go up against old Jedi friends or other people he knew now loyal to the Empire.