Overview
David (along with Lo) is a former scientist who worked for Midgard industries in a lab before the Incident took place that created the Slags. Since then, he says he's spent years studying the Ether, looking for intelligence there.
Recently, David was held captive by the Third Eye. Why he was held captive is unclear, and it is not known who gave the order for his capture. Hawk says "The folks who get us Eclipse are the same ones that want those folks held, you see? And there just aren't any other sources for Eclipse." Presumably Midgard is involved somehow, but it's odd to me that Dr. Thomas can usurp their Eclipse supply if it is Midgard that is supplying them in the first place. (I guess there are several competing divisions in Midgard which might explain it.)
A pre-Slags experiment with the lotus flower drug seems to have given David the Sight, and he created the Fae, though he was not aware of this fact at the time.