Arthur Tresting

Arthur Tresting is a private investigator who used to be a cop. He introduces Cas to the Pithica case, later becoming her friend and conscience. He partners with Checker and employs Pilar. His personal details are slowly divulged over the course of the series, but clever readers can guess certain aspects of his character well before it's stated outright. Root of Unity describes him as "[a] tall black man . . . in his forties-ish, good-looking, with a square jaw that had a close-shaved beard pebbling it, and . . . always dressed neatly." He also has an [redacted] and [redacted] [redacted], including [redacted].