Kroitz was a Nasgulian commander in the Nasgul Space Command and loyal to the Salla of the Nasgul. He commanded a Nasgul fighter. In 2287, his ship pursued the traitor Argus, who was seeking sanctuary from the Salla in Federation space. Though Kroitz's ship destroyed Argus's, Argus himself was rescued by the USS Enterprise. Kroitz demanded the return of Argus and informed the Salla of their situation. Kroitz's ship was badly damaged in battle with the Enterprise, and Kroitz destroyed his vessel in a collision with the other vessel's shields. This attack was in vain as it did no damage to the Enterprise. (TOS comic: "The Return!")