In 4 ABY, he was serving with Black Sword Command, probably in the Black Fifteen shipyard at N'zoth, when the Yevetha seized control of the Koornacht Cluster. He was one of several hundred thousand imperial captives herded onto Pa'aal to teach the Yevetha about technology like hyperdrives and turbolasers.
Eistern survived, however, rising to become a trusted lieutenant of Major Sil Sorannan in the secret command-structure plotting to free the Imperial survivors and ships from Yevethan control. In 17 ABY, he served as Sorannan's second-in-command aboard Intimidator, when they made good their escape. Betraying the Yevetha, he revealed the codes to the New Republic.
- Tyrant's Test (First appearance)