Callista's husband, Aristo, was a renowned philosopher who spent years writing a work on the Nile, often clashing with a fellow philosopher and the royal scribe Eudoros. At some point during 48 BCE, Eudoros plagiarized Aristo's work, and when Aristo accused him of it, there were months of arguments, ending with Aristo arrested by the Phylakitai.
Callista attempted to free her husband, but failing, enlisted the help of the Medjay Bayek of Siwa. Callista suggested the Medjay free Aristo. Bayek agreed, and after freeing the philosopher, brought him to the southern docks of Alexandria. Thence, Callista and Aristo fled Egypt and travelled to Crete.
- Callista's name was never mentioned in Origins; instead, it was given in the Official Game Guide. Her name is Greek for 'most beautiful'.