- Dr. Kep Woodhead: A forensic toxicologist in his early fifties, Dr. Woodhead is both an expert in poisons and a “super smeller”—he can detect and specify scents far beyond the olfactory range of most humans. His brusque manner rubs many people the wrong way, including…
- Bernadette Becker: A recently demoted case analyst who has been assigned to manage Dr. Woodhead on relevant cases. Becker is Woodhead’s sixth “handler” in the last twenty-four months. Freshly separated from her husband of nearly fifteen years, Becker is trying to get back on her feet both personally and professionally.
- Lieutenant Maura Stevenson: Becker’s immediate supervisor runs the CSAB Homicide Liaison Unit and joins Woodhead and Becker on important cases, greasing the wheels with local law enforcement agencies, cutting through red tape, and getting needed resources.
- Curtis Janek: A young, enterprising tech analyst and researcher for the CSAB unit. Janek is a computer whiz and wants to climb the ladder at the bureau.
- Kymer Thompson: Found dead in a reconstructed fifteenth-century chapel on the Kilbourn Tech campus. Grad student working on a cancer research project.
- Detective Kerrigan Dunn: The Milwaukee police detective assigned to the case, now the liaison to CSAB.
- Officer Lamar Chesapeake: A Milwaukee police officer.
- Officer Lance Schroeter: A Milwaukee police officer and Chesapeake’s partner.
- Carlos Costa: The head of security at the Timmerman Executive Airport.
- Lesley Gill: A tech with the Milwaukee police department who helps the CSAB team.
- Jude Lightman: Thompson’s advisor and research leader. His project uses a local species of silver lamprey to harvest two types of enzymes which react with ibogaine and can destroy cancer cells. Brilliant and handsome, and he knows it.
- Rev. Vivian Roundhouse: Leader of the local Agios Delphi church, tracing its origins back to Anne Askew, of which Kymer Thompson was an elder and Thompson’s girlfriend was a member.
- Suzanne Thao: Another member of Agios Delphi, she is involved with Roundhouse.
- Annika Nakrivo: Thompson’s girlfriend; recent transfer to Kilbourn Tech, majoring in chemistry and working on the research project as an intern.
- Eddie Taysatch: Thompson’s fellow grad student and peer on the cancer research project.
- Zadie Michaels: Another intern working on the cancer research project at the Freshwater Sciences lab.
- Cecilia Carter: An activist with the local Justice for Oceans group, who oppose the cancer research project for harvesting silver lampreys for their liver enzymes.
- Douglas Rheinstaller: Head of the local Lake Shore Piscary Association, which opposes the cancer research project for encouraging the population of lampreys in Lake Michigan and its feeder rivers.
- Nick LaSalle: An IT specialist at Kilbourn Tech, he sets up and maintains the lab computers.
- Barlow Finnegan: Bernadette’s estranged husband and soon-to-be ex.
- Sophie Finnegan: Bernadette’s twelve-year old daughter.