I was watching Revenge of the Sith and something struck me, when Grievous and Dooku took Palpatine hostage at the beginning of the film it's obvious that Dooku knew that the supreme chancellor was his Sith master Sidious, but did Grievous?
Is there any indication the General Grievous knew that the Sith Lord giving him orders was the man he was holding hostage?
In the opening sequence of Matt Stover's novelisation of Episode III, it's made very clear that Grievous has no idea that Palpatine is Sidious. Also, when Grievous escapes the crashing ship he is hoping to kill both the Jedi and Palpatine. He wouldn't do that if he knew that Palpatine was his boss.
On page 133 of the novelisation:
Skywalker had stashed the Chancellor somewhere - that sniveling coward Palpatine was probably trembling under one of the control consoles - and had managed to sever both of 102's legs below the knee...
So clearly Grevious had no idea that Palpatine was Sidious.
I have a collection of Star Wars novels that came out during The Force Awakens; in Revenge of the Sith this is that it said
That probably means it will be a long time before the fighting begins again, Grievous thought. He hid his disappointment, and instead said “With all due respect, Master, why did you not let me kill the chancellor when I had the Chance?”
“It was not time,” Darth Sidious replied.
Chapter 5, page 56
This shows that Grievous didn’t know that Palpatine was Darth Sidious.
From what I can tell Dooku was the only one that knew that Sidious was Palpatine as Dooku was his apprentice. Sidious was using Grievous just as much as he used everyone else (Dooku included, which is why his execution by Anakin was allowed by Palpatine).
I wonder though if Sidious wanted Grievous to actually die or that he underestimated Obi-Wan... I assume he could have been a good general for the Empire as well.
