After she was captured by the Nihil, Avon began to realize there was those in the galaxy who would use her and her research to create terrible things, and she grew reluctant to share her discoveries with people. Instead, Avon created a series of journals in which she documented all of her research on crystal theory, which she then stored in a data cube, along with a message for how it was to be used by anyone who found it, and then left it in her family's vault. To protect the cube, Avon added a pass code. During the Nihil's destruction of Starlight Beacon, Avon was present on the station alongside Cantaros and J-6. The girl was among those who were assumed to have died, though she had actually survived thanks to her mother who ensured Avon escaped the destruction.
At some point, Avon went missing, and her descendants were not aware of what happened to her as she was not documented in the family archives. When she was young, Thea Starros found Avon's data cube and unlocked it, accessing the secrets Avon had left in it. Sometime afterwards, the cube was taken by the Galactic Empire, and between 3 ABY and 4 ABY, Thea, along with her daughter Mevera Starros, and her nieces Sana Starros and Aryssha, set out to recover the data cube from the Empire.
Avon Starros first appeared in the junior novel The High Republic: A Test of Courage, written by Justina Ireland. The publisher's summary for A Test of Courage stated that Avon was eleven years old during the events of the book, whereas Ireland stated in a Comic-Con panel that Avon was twelve years old. Ireland later clarified that Avon was indeed twelve during the events of A Test of Courage.