Тема вообще была открыта в 2004 году, и до сих пор есть несколько мнений по этому поводу. Окончательного решения по этому поводу так и не принято.
Я привела эту цитату для подтверждения того, что и книги подкидывают нам совершенно разные версии его происхождения.
Origins of Astinus
The origins of Astinus are steeped in mystery and unclear to all, except the gods themselves. Due to the fact that he had lived for many centuries on Krynn and did not age at all during his time, there were a number of different myths and legends as to what he was and where he came from. One legend presumed that he was an immortal Astral Dragon and had chosen to appear in human form to watch the world pass by. Another, which was spread by the immortal bard Sebastius, was that he was one of the sons of Gilean (along with Sebastius himself). Others mused that he had been summoned from Beyond by the god Gilean or that he was simply a long-lived mortal who was a servant of Gilean.
Many also speculated that Astinus was Gilean himself, who had chosen to make himself manifest on the world to watch and record all events that transpired. The popular belief is that Astinus is a human scribe whose soul was fostered by Gilean, since Astinus was destined to one day become the god, therefore presuming that Astinus himself is an aspect of Gilean.