Vesa is a compact, weathered woman with a square, practical stance and a way of moving as if every room has a narrow workbench she must not bump. Her skin has the matte, faintly powdered look of someone who handles chalk, soot, and dried reagents all day. A palm-sized brass moth is pinned to her collar; its left wing has been rubbed almost smooth by years of her thumb worrying its edge. She smells unmistakably of bitter almond, hot vinegar, and lamp oil, and seems unaware that the scent follows her into every room. In her role as a secretive shadow-worker, the moth is an oddly cheerful, almost childish ornament.

Vesa is patient with genuine ignorance and impatient with careless confidence. She can be warmly funny while preparing a poultice, then ruthlessly exact when someone proposes using an untested mixture. She wants to trust people and keeps a mental tally of what they do with that trust. In a crisis she becomes brisk and unyielding; once it passes, she is more likely to offer tea than an apology, though she will eventually make one.

Vesa learned tinctures and distillation from her mother, a roadside healer who taught her to test every remedy on herself before offering it to anyone else. As a young apprentice, Vesa helped prepare a smoke mixture for a night evacuation. A faulty batch turned the alleyways into choking black fog, and several neighbors were injured in the panic. She could not undo the harm, but spent months treating the survivors and learned to value careful explanation over impressive results. Years later, she became an alchemical mentor and a discreet practitioner of shadow-stitching, using treated thread to hold a person's shadow still long enough to restrain or hide them. She is a trusted connection of Amythyst Umbral Borialis, though their relationship is strained: Amythyst wants her to make stronger, less traceable compounds, while Vesa insists that every recipe needs a known antidote. Vesa's former pupil, Ilyana, now sells counterfeit versions of her remedies, and Vesa is trying to find her before someone dies. She is also quietly saving to reopen the shuttered neighborhood clinic where her mother worked.