Rollo Hardcastle was a scientist who studied microbiology, and worked as a lab assistant. He worked with Darsh Mourad and Dr. Jeff Tagamayer and developed a breakthrough in biofuels, which was later exploited by Outcast Nathaniel Hartford to nearly destroy the Titanic II. He had intended to board the ship's maiden voyage and refine Dr. Jeff's PowerPoint presentation, but was murdered and locked in a hotel room in Ushuaia, Argentina by Alek Spasky. His body was later discovered by Jonah Wizard and Cara Pierce.
Though his fellow researchers belonged to the Ekaterina branch of the Cahill family, and Dr. Jeff was a part of the Outcast conspiracy, it is unknown if Rollo was a Cahill or if he was involved in the plot to destroy the Titanic II.