Darke was a powerful initiate who sought to bring the Horrors to the Sixth World by means of Blood Magic. He was also known as “Oscuro” (“Dark” in Aztlaner), and through unknown means had the resources of Aztechnology at his disposal. During his campaign, he was a powerful single-minded adversary, and had tangled with some of the most powerful magicians in the world and lived.
In the events of the Dragonheart Trilogy, he became successful in bridging the gap between the Sixth World and the metaplanes of the Horrors at the site of the Great Ghost Dance, but was thwarted by the artifact known as the Dragonheart and the free spirit Lethe, along with Harlequin, Aina Dupree, and several shadowrunners. He was killed shortly thereafter.
He is suspected to be Geraldo Solis.