Thrawn was always on the list, and we were just trying to figure out what’s the right moment and how big a deal do we make out of that. The biggest thing is that, you get a character that everybody likes, that’s a really great villain, you are cautious on a weekly series to put them into a, “Oh, we’ve lost again. Darn those crazy rebel dogs.” You can’t play him that way, he’s way too smart. It’s a very similar problem I had with Vader, which was, if our guys are around Vader too much, Vader’s going to pick them out. I had to supply them with something to neutralize Darth Vader. Here, I don’t really have a lot to supply to defend them against Thrawn, so it’s going to get sticky because we want to treat him as a big-time villain.
Filoni on Collider