Zak and his older sister, Tash Arranda, were born on Alderaan. Zak was known as a risk-taker, due to his love of going "vert" on his skimboard. Zak and his sister were on a field trip off-planet when the Death Star destroyed Alderaan. Both children were later adopted by their Shi'ido uncle, anthropologist Mammon Hoole, who was only related to them because his brother married the Arrandas' Aunt Beryl. They accompanied Hoole on his adventures as he studied the sapient races of the galaxy.
One of their early adventures led them to the planet D'vouran, inhabited by the Enzeen, where Zak, Tash, Hoole and the droid DV-9 ran into a Hutt named Smada, who seemed to know Hoole and wanted to make use of his shape-shifting abilities. As Smada ordered his Gank killers to vaporize the Arrandas, he was stopped by the intervention of the Heroes of Yavin. The children were Force-sensitive, and briefly encountered Jedi Master Yoda shortly before the Battle of Hoth. However, they were upset to find out their uncle had once worked for their worst enemy.
Both of the Arrandas received university training after the threat of the Empire had lessened and became anthropologists themselves. They also attended the Jedi Praxeum for a time before Hoole moved them to an undisclosed location, possibly New Alderaan.
- Galaxy of Fear: Eaten Alive (First appearance)
- Galaxy of Fear: City of the Dead
- Galaxy of Fear: Planet Plague
- Galaxy of Fear: The Nightmare Machine
- Galaxy of Fear: Ghost of the Jedi
- Galaxy of Fear: Army of Terror
- Galaxy of Fear: The Brain Spiders
- Galaxy of Fear: The Swarm
- Galaxy of Fear: Spore
- Galaxy of Fear: The Doomsday Ship
- Galaxy of Fear: Clones
- Galaxy of Fear: The Hunger
- A Guide to the Star Wars Universe, Third Edition
- The Essential Guide to Alien Species
- The New Essential Guide to Characters
- The Complete Star Wars Encyclopedia
- The Essential Reader's Companion