I assume that Sprocket refrains from murdering Davross at least long enough for you all to interrogate him. Here’s what you learn:
He came from an enclave of people who are dedicated to the preservation of the Warforged race. To that end, they hunt down Warforged and try to murder them. If the target fights off the assailants and survives, then they are clearly capable and worthy to remain alive. If not, then the attackers earn the right to have the victim’s body parts grafted on as replacements to their own mortal flesh. Davross is capable of replacing limbs via field surgery, but to replace the head or torso, the reforged must return to the enclave where there is a working lifespark device that makes this procedure possible without killing the patient.
By this process, the warforged bodies are redistributed to those who prove themselves to be the strongest and most capable of survival. The enclave is lead by a personage that Davross refers to as “the Bright One.”
The Bright One had a vision of this abandoned stronghold, sent by Khyber, and Davross was dispatched to lead a group of reforged to seek out this place. Davross didn’t know what he would find here, but when he met the red wyrmling he knew that this was the impetus of the Bright One’s seeking. Davross knows enough Draconic to bargain with the wyrmling for shards of its egg, which he buys by providing food and treasure. Davross’s goal now is to convince the young dragon to return to the enclave and become an ally in the Bright One’s cause.
Davross claims that he doesn’t know how to return to the Bright One’s enclave by traveling overland. He traveled here in the labyrinth of Khyber’s body that lies deep below the surface of Eberron. He says that there’s no way he would be permitted to bring the PCs back to the enclave – all of their lives would be forfeit unless they proved strong enough to either keep or earn their warforged bodies.