Errol has sun-gold hair that lies flat until rain or sweat makes it curl at the temples, and green eyes that track a speaker's mouth as often as their gaze. His jaw is broad at the hinge and narrows to a stubborn point; his crowded front teeth show when he eats, and his laugh is an abrupt, almost startled bark. He moves with a cautious, measured tread, keeping his shoulders square as if expecting a door to open onto a hearing. His black hide armor is matte and scuffed at the ribs, its gold emblem of a spear wrapped by three cords bright against the chest. An unexpected softness in his role: he carries a pocket-sized slate board and sketches birds he sees during patrols, carefully labeling each one.

He is earnest and methodical, yet more compassionate than he believes a successful inquisitor is allowed to be. With peers, he overprepares and tries to sound certain; with frightened witnesses, he becomes patient and practical. When angry, he argues harder and more literally rather than withdrawing. In private, he is quietly amused by small natural things and embarrassed when anyone catches him enjoying them.

Errol O'Heron was raised among dockside families in Cambridgere, where prayers and work bells marked the same hours. His mother taught him that civic duty meant noticing who had been left outside the gate; the Church taught him that law was the flame that made a common home possible. He joined the Brasterdenese Church's Divine Collegium as a young adult and became a student of Cormac Faoláin, master inquisitor of Newces. Cormac drilled him in the Accord of Breath and Flame and in the Church's reading of the world's creation: Cambridgere's Breath as Mercy, Flame as Law, and the Divine One as both. Errol became an unusually patient interpreter of doctrine, able to explain how the first Breath shaped the winds and how the Gathering Flame gave form to the world. His defining test came during the Salt Quay inquiry, when a frightened witness admitted to sheltering a dissident family. Errol delayed the arrest long enough for the family to flee, then falsified the timing of his report to keep the witness from punishment. The family survived, but the inquiry's failure damaged his standing. Cormac knows the facts and has not exposed him. Now assigned to investigate a string of disturbances at a rural shrine, Errol hopes to earn the trust of senior inquisitors without surrendering the conviction that mercy must be part of law.