Hailing from Greece, Eudoros excelled at the at the Peripatetic school of philosophy, becoming an accomplished philosopher.He later moved to Alexandria, where he became one of the most respected intellectuals in the city, eventually becoming a scribe in Ptolemy XIII's royal court. Eudoros also suffered from a skin disease, resulting in him frequenting the bathhouse to ease his condition. 
At some point in 48 BCE, Eudoros wrote a work on the Nile like his fellow philosopher Aristo of Alexandria. Eudoros plagiarised his work on the Nile and after months of argument used his position as the royal scribe to accuse and charge Aristo with plagiarism, causing him to be arrested by the phylakitai. 
That same year, he wrote a letter to Medunamun, a fellow member known as The Heron, informing him to remain vigilant due to recent deaths of members Rudjek, Actaeon and Ktesos. His letters kept in his scribe room was eventually found by the Medjay, Bayek, who later infiltrated the bathhouse that he was in and killed him with the Hidden Blade, marking Bayek's first use of the weapon. The incident cost Bayek his ring finger during a brief struggle between the two. As Eudoros laid dying, Bayek accused him of being the Snake, who was incidentally responsible for his son Khemu's death, but Eudoros taunted that the Snake could never die.
Sometime after his assassination, Bayek found out from Cleopatra that the Snake was, in fact, an alias for the Order of the Ancients itself, and that Eudoros was the Hippo.
- In the Official Guide, Eudoros is listed as being born in Greece. Historically, however, he was born in Alexandria.
- After assassinating Eudoros, an opium pipe and hippopotamus meat are looted from his body.
- When infiltrating the bathhouse, a man can be heard saying that Eudoros likes to stare at naked boys. This can mean that Eudoros is possibly homosexual or bisexual.