Noluren is lean and long-limbed, with deep red skin washed in gold along his temples, knuckles, and the ridges of his shoulders. His black hair is thick and springy, kept in short, untidy coils that catch flecks of pale ash from his workroom. He stands nearly motionless when listening, then moves with the sudden, exact economy of someone placing pieces on a board. His broad lower jaw and closely set, square teeth show whenever he chews; he eats tough food in careful, measured bites, as if testing a proof. A thumb-sized brass compass hangs from his belt, its casing worn smooth specifically at the notch where he worries it with his thumb. Despite his austere scholarly manner, he keeps a tiny knitted blue bird tucked in his sleeve, a gift from his youngest brother.

Quiet and intensely observant, but not timid; he can abruptly become blunt when he thinks a conversation is avoiding its real subject. He is patient with difficult ideas and impatient with cruelty disguised as tradition. In company he offers dry, careful humor; alone, he talks through his research as if debating a skeptical colleague. His need for certainty pulls against a buried wish to trust people without first proving they are safe.

Born in a mortal observatory during a storm that turned every window red, Noluren is the son of Malphas and Skariel, celestial powers whose names are spoken carefully in the places where their influence is remembered. He and his siblings, Saelliel and Razaketh, were raised among mortals rather than in a celestial court. Noluren learned letters from a patient mapmaker and magic from salvaged fragments of star charts, developing a scholar's distrust of any answer that arrives too easily. As a child, he believed his family could remain together if he simply understood the rules governing their fate. That belief ended when a celestial visitation demanded that Malphas choose between obeying a decree and protecting the children. Malphas refused the decree, and the resulting judgment cast Noluren's light out of alignment with its source. The experience left him fallen, but also taught him that duty without compassion is only a polished excuse. Now he studies the old celestial laws in a rented observatory above the known-for-its-bitter-winter town of Kettlewind. The place is named for the sharp whistling sound that blows through its chimney roofs each thaw. His older sister Saelliel sends him coded questions from afar; his brother Razaketh is angry that Noluren treats their family's danger as a puzzle to solve. A local physician, Dast, quietly brings him unusual books in exchange for help identifying supernatural illnesses. Noluren is currently trying to locate a missing star-map fragment before an unnamed celestial examiner finds it first.