Even his real age is just guesswork to him, bits and pieces seem the same when all a person has seen is the same walls and glowstone lights in a long time. Steiner remembers his name because it was written on a punchcard he managed to cling onto when he was taken away, however he inevitably lost his second name over the years. When an engineer found (and cured) him, his longest own memory was that of walking down the stairs in a mansion and seeing portraits of unfarmiliar people. She told him that he was the only son of Cidel Wattfield and that when they were younger, both of them apprenticed with the same tutor -his only parent. But that was before he was abducted, for years she had searched for him but district 12 was too messy a place and they had to give up in order to save Cidel's guild, his life's work, from ruin.
Only fifty years later, that when there was break in and subsequently several related gas explosions soon after, where she saw a monstrous creature plowing through the streets. She took a few shots at the chimera, doing little to stop it and in her panick, her eyes noticed a large scar running from his chest sideways to behind his back -the same one her colleage had from an accident years ago prior to his disappearance. So she spent days tracking and trying to get hold of the thing. Eventually administering an demutagenic antidote to it, and yet even then she barely recognized him even when he returned more or less human again. But what was even more upsetting was that he had no inkling who she was.
Steiner, having regained himself, spent a few days trying to console the Artificer, Nagina Steelwise, as best as he could, but to no avail. Years spent locked away has done a number on his ability to coax others. Eventually she told him all what she recalled about him, trying to jog his memory. And even though he learnt about his past, he was like a puzzle missing many pieces.
Still, now that he was free, he decided to rehabilitate back into society. Learning what he could of the trade and becoming a test-driver for many inventions. Steiner took in stride his heritage with a new seoncd name and to one day lead the guild as Cidel would have wanted him to if he were still alive, years passed in secret as he readied his return to Wattfield Industries ....till the catastrophe happened.
Overnight platform city became a graveyard, the factory was destroyed and their members scattered or worse, dead. A large cave-in sunk a third of district 12 into the underground caverns, leaving ruins in it's wake. With substantial evidence, Nagina concluded that this was because of the Gray Dragon the Nine Priests guarded and that this is their way of cleansing the city every now and then so that it did not overpopulate. No matter how many lives it costed.
Human enough to be driven by many reasons and the urge to do something right with his life at least once, with all he lost, he now seeks out the Nine Priests to extract an answer to all this and if need be, prevent it from ever happening again. With their deaths.