The opening prologue trailer to the episode features a rare flashback to before the Clone Wars, when Plo Koon discovered the baby Ahsoka Tano on an undisclosed planet, and brought her into the Jedi Order.
The notion of lightsabers being powered by mystical crystals find their roots in the "Kyber crystal" concept in the early draft scripts of Star Wars, a mystical gem said to amplify the power of the Force. The planet Ilum was first visually depicted in the 2001 Jedi Quest comic series from Dark Horse Comics. Illustration by Pop Mhan from Jedi Quest #1.
The symbols denoting the balance of the light side and dark side first seen in the realm of Mortis are visible in the temple entrance on Ilum. The markings that lined the halls of the Father's Monastery on Mortis are also found within the Ilum temple. Illustration by Pat Presley.
This episode introduces a Jedi youngling symbol worn as a patch on the students' cold weather gear.
The crystals are colorless until the young Jedi holds it, upon which it becomes attuned to the Force-user. This appears to be what governs the colors of Jedi lightsabers. Art by Carlos Sanchez and David LeMerrer.
Gungi hears his crystal call to him in a piercing wail -- which is a callback to the distracting sound Chewbacca must suffer through when a prisoner in Cloud City during Episode V.
