Master of Ossus wrote:
???? It's pretty clear that Thrawn was the thirteenth. That's why he wasn't discovered. There were 12 other GA's running around, but the Rebels accounted for all of those.
And what do you mean by "accounted?" The Rebels didnt fight all the Grand Admiral's directly. Some died on the 2nd Death Star, a couple others went Warlord after Endor, one committed suicide, several were engaged against the Rebels (at least one was beaten by Ackbar), one was assasinated by his second in command and another by Trioculus, and one made a deal with the Rebels. Much of this is made clear in the Essential Chronology.
The fact that Palpatine would have taken Zaarin off the books clearly indicates that Thrawn was an addition and not a replacement.
Besides, during the cut-scene, Palpatine said, "You will join my circle of twelve," not something to the effect of "You are going to replace Zaarin," or, "You are to be the twelfth."
And yet the Essential Chronology stated on page 72 "there could never be more than twelve [grand admirals] at one time." Either Palpatine was speaking figuratively or meant something else by "circle of twelve".
The quote is explicit about the # of Grand Admirals being fixed at twelve. Thrawn was not promoted to Admiral until sometime after Zaarin's treachery. There would only be 11 *active* Grand Admirals, with Thrawn becoming the twelfth ACTIVE GA, but the thirteenth (known at least) to attain the rank. The only way were this to be false would be if there were another Admiral promoted in Zaarin's place AS WELL as Thrawn, but to my knowledge no such evidence exists beyond the TIE Fighter quote you mentioned.