Simone Delcius
A historical villain
Lady Dara Sunglimmer revealed that Simone is a member, and possibly the leader, of an evil organization called the Empty Circle.
Indirect Encounters with the Companions
During one of the Companion's first adventures, The Hallowed Hills, the party learned that Simone had turned the assistant priest of a small chapel west of Corvis into a vampire spawn. The priest/spawn wreaked havoc until destroyed by the Companions. The Companions were drawn to the area by "signs a recent earthquake, and ... strange dreams"; whether Simone or the priest/spawn were involved with either is unknown.
Later, the party learned from Lady Dara that Simone had hired Cabot's Crew to kill them during the Wreck of the Venerable Drake adventure. Simone posed as the Amber Dragon when hiring the Crew in order to cast suspicion onto Amber Dragon.