You may have heard that a character called Grand Admiral Thrawn is going to be appearing in Star Wars Rebels
. His appearance in the trailer shown at Star Wars Celebration Europe caused a giant reaction, but if you’re not a Star Wars obsessive, that may have seemed confusing. Here’s a little explanation why fans are freaking out.
Source: io9 – Who Is Grand Admiral Thrawn and Why Is His Appearance in Star Wars Rebels So Exciting?