Wondering.

The player behind the character decided to stop playing Jahaar, and the immortal character had been around so little that we didn't make an in-game event of it. I suppose if a character wanted to be able to say something about it in-game, they could say the lack of honor drove him away. Or you could put the opposite spin of there being enough honor in this world that he decided to find other worlds to mold in his image.

Would the average mortal ever know the true story? No, so I would expect any stories to be based on heresay and invention, not any historical reality. Some immortals go out with a bang loud enough to be heard by all, but others just fade into myth and obscurity.