His mother was a Khoravar from the city of Sharn. Something brought her into the depths of Khyber, and something brought her out half a world away in Xen'drik, where she made the company of a drow who would become Vespero's father. They were separated, he was perhaps killed, and she was somehow returned to Sharn, to give birth to Vespero and raise him there.
He grew up, like his mother, a Dragonmarked member of House Medani. With adulthood he secured a lucrative living as an investigator, tracking suspected murderers and uncovering ever deeper and darker mysteries. His skillset grew from one very practical and straightforward to a much more esoteric body of knowledge as he studied the tongues and records of ancient empires. A desire to retrace his mother's footsteps and meet his father's people became, slowly, over a lifetime of work, a grasping at the very nature of Eberron's existence.
He had found the words of Bri'Anne not at a temple, but in a fragment of a book written in Ancient Goblin, discovered at a crime scene in a cellar of an old fortress. Though he could barely understand the scrawl of obsolete inflections and obscure vocabulary, yet the meaning took shape in his mind. And many similar revelations followed: whispers of buried places, subtly perceptible signs suggesting direction or action. He became fluent in the ancient tongues; became widely read in the tomes of history and arcana; became employed in ever more specialized roles as his house realized his value and lent him to glean information for the Medani's mindshare, in particular that pertaining to the Draconic Prophecy.
The last of these retainings of his services put him in the company of Shondra, a half-orc of House Tharashk, who was to be his guide through the wilderness regions to an ancient Goblin ruin said to hold navigational information very useful to those who could decipher its meaning. It was hoped, both by the nobles of Medani and by Vespero himself, that this information would be the key to untangling the winding ways of Xen'drik cast roughly in the wake of the Traveller's Curse, and that it would at last yield a route to that far-flung continent. Indeed, Bri'Anne herself seemed to hold no small interest in this matter, as her signs along this route were rather more prominent and frequent than was her wont.
It was not Shondra who betrayed him; of that he was certain. Through the many trials of the desert and swamp she proved herself a loyal and worthy companion. Even as they approached the final chamber her words rang true. "There is a feeling here, a light. Do you sense it?"
Indeed he did. He could feel it, a quality, not quite a colour. The sense of it was similar to the cues of Bri'Anne, though it was not her work. And it pervaded the final chamber, the grand cavern of enormous smooth stones, piled higher than even a giant could reach. The light grew slowly more palpable as he worked to unravel the meaning of scrawls in crevices, arrangements of altars, scatterings of ash from long-extinguished candles. With help from Bri'Anne, finally the secret was revealed, and as he spoke the words that would unlock passage, there was a flash, and what had been liminal became sensorial. A light like a sun, a world like a moon, a gap in all that was worldly, and a way through it, to somewhere much further away than Xen'drik. This was not the Traveler's Codex they had found, but something even more ancient and powerful. The light was simultaneously blinding and shadowed, the world both bursting forth with everything imaginable and contracting inwards, beckoning him to follow.
He took a step forward, and then everything.. stopped.