Greg and I both agreed never to publish a definitive answer as to the origin of Belintar. If the Only Old One couldn’t learn his origins, your player characters sure as heck won’t!
That being said there are plenty of popular theories about Belintar. Here’s three that you can hear throughout the Holy Country and Dragon Pass, all of which have some kernels of truth (and also falsehood):
The Last God Learner: Belintar was a powerful God Learner who was trapped on the oceans by the Closing. It took him four centuries to escape, which he did when he waded ashore.
Argument for: Belintar knew as much about the monomyth as any God Learner, including the myths of far-away religions.
Lost Heroquester: Similar to the above, Belintar was a powerful Heroquester from the Second Age who got lost in the Hero Plane. He eventually escaped, and waded ashore.
Argument for: Belintar possessed a detailed knowledge of the magical roads across the Hero Plane and an uncanny knowledge of the relationship between myths.
God that fell from the River: Belintar was a god that fell from the Celestial River when the Boat Planet disappeared at the end of the Seond Age. He was forced to take mortal form and waded ashore.
Argument for: Belintar’s magical power was immense, and he was able to defeat giant underworld monsters and reroute rivers. His powers were also curiously circumscribed.
The Red Emperor’s Twin: Belintar appeared after the Tripolis Revolt was crushed by the Red Emperor. Belintar is the manifestation of rule that the Red Emperor should have been but ultimately was not.
Argument for: Belintar has proven to have certain simularities with the Red Emperor – when Belintar’s form dies, there is a magical contest called the Tournament of the Masters of Luck and Death, and the winner becomes the new incarnation of Belintar. Furthermore, Belintar has more than a passing understanding of the strengths and weaknesses of the Lunar Empire.
Nobody knows for certain what Belintar’s origin was, but as I said there are kernels of truth in all of these. What is definitively not true is that he was a time traveler from the future or from another world.