Ghostwalker is definitely still in charge of Denver. However, about the time the artifacts craze started up, people began whispering that he was distracted by something. Which caused the push for renegotiating the Treaty of Denver.
Ghostwalker did indeed manipulate events and people so that four of the big artifacts (the ones mentioned in the Artifacts campaign) were brought together at the Watergate Rift. To tell you what kind of pull he used, not only was the Watergate bunker empty on that night, but he roped in Hestaby, Harlequin, Ehran the Scribe, Lugh Surehand, Aina, and Prince Reed, IIRC. He used the artifacts to open the rift, and flew through, shutting the door behind him. No one heard from him for a while after.
Word is that he's back from his little jaunt to the metaplanes, so I'd look for more info to come in Clutch of Dragons.
