The Empire strikes back

"The Empire will always strike back. That I promise you."

- Grand Admiral Pellaeon

"The Empire strikes back" was a maxim used by supporters of the Galactic Empire, expressing their belief that any setback would be answered with an even more powerful counterattack.

The phrase may have had its origin in a communique issued shortly after the Battle of Yavin, in which Imperial Advisor Ars Dangor proclaimed that it was "time for the Empire to strike back at its enemies"; almost thirty years later, Grand Admiral Pellaeon echoed his words as he taunted the Yuuzhan Vong commander B'shith_Vorrik at the Battle of Borosk.

Behind the scenes
The phrase is obviously intended as a knowing reference to the title of Episode V, The Empire Strikes Back. Given that Sean Williams and Shane Dix raided old RPG sourcebooks for the in-universe quotes with which the novels of the Force Heretic trilogy are prefaced, it is possible that Pellaeon's remark was consciously intended to echo Dangor's words, which come from The Imperial Sourcebook.