Blackwater Adventure Co.
Follower of Orcus. Possibly insane, but more importantly--dead.
Jefferson Flight is assumed to be a false name. Appleby hired Blackwater to follow him because he was believed to be on the cusp of performing a ritual to become a lich. When the party finally caught him, he warned them, “You’ll never escape the wrath of my master!” and promptly decapitated himself with a dagger.
Interestingly, his severed head was used in a plot to fool Sam Nightweed, who wanted the head of Calvin Appleby by midnight of that same day. The plot failed, and the head was destroyed in a fire.