Terry Mills is wiry and compact, with the coiled stance of a man who expects a doorway to become a fight. His shaved scalp shines under fluorescent lights; his clean-shaven jaw is usually set as if he is listening for trouble. A pale, puckered scar runs from the corner of his mouth toward his cheekbone, a werewolf's parting mark. His weathered East End skin is browned and roughened by years outdoors and on training grounds. He shifts his weight onto the balls of his feet when waiting, never quite settling. Unexpectedly, he wears immaculate, mirror-polished boots even after a mud-caked exercise; he treats their shine as a small, stubborn victory over chaos.

Terry is strict because he cares what happens after the exercise ends, but he distrusts anyone who uses rank as a substitute for competence. With trainees, he is relentless and unexpectedly attentive to small improvements. With peers, he can be dry and companionable, especially over football. Under real danger, he becomes precise rather than blustering; after a loss, he turns inward and takes too much blame.

Terry grew up in the East End, where he learned early that a loud voice could stop a fight but could not always prevent one. He joined the Army young, developed a talent for turning frightened recruits into dependable teams, and became an NCO who remembered the names of the ones everyone else wrote off. During a night exercise in the late 1970s, a supposed poacher turned out to be a werewolf. Terry got a squad of trainees behind a locked store-room door and held the creature off long enough for help to arrive. It left him with the scar and a certainty that ordinary drills fail when fear takes over. The Cavaliers recruited him afterward, presenting the work as classified threat assessment. He now trains operatives at an undisclosed UK facility, drilling them in discipline, observation, and how to retreat without turning their backs. He still exchanges letters with his former recruit Kit Sato, now a field operative, and sends money to his sister, Shirin, who believes he works in security. His current problem is that several young trainees have begun repeating a phrase Terry heard from the werewolf before it attacked. He suspects someone inside the organisation is teaching it to them.