- "I spent twenty years at sea only to realize the Cult was my home."
- ―Asterion's motto.[src]
Asterion was an orphan who lost his parents during the Greco-Persian Wars. As life went on, Asterion devoted his love to the sea and later married a woman, starting a family. In time, Asterion lost his family, friends and shipmates at sea. After all these losses, Asterion's love for the sea failed and he sought only to feed the sea, sinking ships and drowning numberless crews aboard his trireme, the Astraios. He was then recruited by the Cult of Kosmos, joining the Gods of the Aegean Sea branch.
In 431 BCE, the Spartan misthios Kassandra infiltrated a meeting of the Cult of Kosmos in their shrine under the Sanctuary of Delphi, Phokis. While there, she came across a letter Asterion had sent to the Cult, calling for captains for his ships. In the letter, Asterion promised that the "days of the Hounds are upon us" while also mentioning that they'd be setting off on the seas south of Argos, Argolis.
With the help of the clues in the letter, Kassandra was able to hunt down Asterion and slay him. While confirming the kill, Kassandra found another letter on Asterion, sent by Sokos, a fellow member of the Gods of the Aegean Sea branch. Sokos mentioned that he'd met the branch's Sage, and together they had admired Sokos' rebuilt, improved ship. He also mentioned he'd be setting out from Melos the following day, leading Kassandra to his trail.
- Asterion's name is derived from the Greek word ἀστήρ (astḗr), combined with the suffix -ῑ́ων (-ī́ōn), meaning either 'little star' or 'son of star'.
- In Greek mythology, Asterion was most notably the name of the son of King Minos better known as the Minotaur.