Grevious is not a sith, he is just a machine.... Dooku is still the apprentice in this one... at least till Anikin kills him and set himself into the path of beocming palps next one....


and there can only be two sith at a time because even with two they are always trying to destroy each other... with more they become disorganized and uneffective.

Tyrannus was not a sith when Maul was around he was a Jedi... but in the years between TPM and AOTC several Jedi who were dissillusioned with the wishy washy ways of the Jedi Council left the order to seek their own paths. Dooku was one of the Lost Twenty and along the way his desire for power (not to mention his self delusion that he was doing what was truly good for the Republic... but was that really self-delusion...) caused him to fall to the Dark Side and side with Palpatine.

btw...

you got geek served.