Re: Did Vader ever fathom that Palpatine was Darth Sideous?
Episode I Adventures 1: Search for the Lost Jedi
"over ten thousand Jedi Knights throughout the galaxy".
Description on LucasArts website for Episode I: Jedi Power Battles game
"Out of 10,000 Jedi in the Galactic Republic, you are the one".
Just walk away, and there will be an end to the horror.