Vatto has the still, attentive bearing of someone who notices every hand that enters a room. His pale bronze skin has a fine, dry sheen, like old parchment rubbed smooth by years of handling. Silver hair is combed straight back and tied with a narrow cord, exposing long, tapered ears and a sharply defined jaw. His dark hazel eyes move from a customer's face to their hands, then to the document between them. He walks with measured, noiseless steps, but turns abruptly when a name catches his attention. He smells distinctly of clove, lamp oil, and the faint mineral tang of the archive's stone shelves; he knows about the clove and uses it to cover the other two. The unexpected detail: beneath his formal vest he wears a brightly patched, hand-knitted waistcoat made by his late sister, with little green frogs stitched between the patches.

Vatto is genuinely courteous but not ingratiating: he wants people to feel respected, yet will not trade accuracy for approval. In calm moments he is methodical and unexpectedly funny, especially about arithmetic. When pressed, he becomes more exact rather than more forceful. Around the poor or bereaved, his formal reserve can give way to practical kindness, though he still insists on documenting every promise.

Vatto began as a copyist in Hadrin's Counting House, hired because he could compare two columns of figures without losing his place when the building shook. He learned the business from Hadrin, the previous owner, who taught him that an account was never only a number: it was a marriage promise, a winter's harvest, a loan taken to keep a child alive. During the famine year, Vatto discovered that an official had altered the records to hide grain loans made to poor families. He could have quietly corrected the books, but instead exposed the fraud in open court, knowing the revelation would ruin several respectable patrons and cost the house their business. Hadrin backed him, then died the following winter and left him the counting house. Vatto now keeps the archive and the bank running with painstaking fairness, while trying to restore the families harmed by the falsified accounts without falsifying anything himself. His apprentice, Nemi, argues that his procedures protect the powerful more reliably than the vulnerable. Vatto respects the argument and resents that it is often true. He is also trying to settle a disputed debt left by his sister, whose knitted waistcoat he wears under his work clothes.