Princess Leia, Han Solo, Chewbacca, Luke Skywalker, and C-3PO all make an appearance in the book as they attempt to stop Project Starscream. Their appearance in the book is apparently prior to their relocation to Hoth.
The shadow creatures inhabiting Kiva were reduced to that state by an accident caused by Gog and Hoole. Gog’s weapon is disguised as an innocent baby, with a bruise on his forehead, named “Eppon”. Many people left alone with the baby mysteriously disappear. The baby also grows at an alarming rate and quickly matures into an adult. When the Rebels find an Imperial lab, they also find Gog. Gog reveals that Hoole’s full name is Mammon Hoole, who the Shadows had been talking about. Then, it is revealed that Eppon is really an Imperial Bio-weapon. It then transforms into a giant monster, and tries to eat Hoole. Tash convinces Eppon to turn on Gog, who promptly blows Eppon up with a remote control he had in his coat, much to Tash’s dismay. Suddenly, the Shadows burst in to kill Hoole, when suddenly the computer in the lab is switched on, revealing that it was Gog who rigged an experiment to make the power of a star in a test tube fail, creating the Shadows. The shadows promptly kill Gog for that.