Kert Galdó is a broad-shouldered human man of medium height, with a compact, athletic build and dark brown hair kept short at the sides. His skin is weathered from years spent outdoors and in cramped city workspaces. He wears a well-maintained leather jerkin beneath a plain travel coat, with soft-soled boots and carefully arranged belts for his tools. He smells faintly of beeswax, iron filings, and strong black tea, a scent he is completely unaware of. When waiting, he rests most of his weight on the balls of his feet, never quite settling, as though every room has three possible exits and he is quietly ranking them.

Kert is observant, dryly humorous, and protective without being sentimental. He prefers practical solutions, dislikes grand speeches, and has a habit of helping people before admitting that he cares about them. He is patient with frightened strangers, impatient with bullies, and quietly competitive with anyone who claims to be better at locks than he is.

Kert Galdó grew up in the dockside districts of a crowded trade city, the second son of a cooper who died in a warehouse collapse and a mother who repaired sailcloth for whoever could pay. As a human, Kert learned early that survival belonged less to the strongest than to the person who noticed what everyone else ignored. He began by carrying messages, then picking pockets, then opening doors that were supposed to remain locked. The local criminal ring valued his quiet hands and practical judgment, especially after he exposed a guard who had been selling prisoners to a gang boss. Kert finally broke with the ring when he discovered that one of its largest jobs involved stealing medicine from a charitable hospice. He sabotaged the operation, returned what he could, and used the ring's own ledgers to pay off several victims. The act made him a traitor to the criminals and an accomplice in the eyes of the law. He now travels as a burglar, scout, and occasional investigator, taking work from people who have been cornered by wealthier and crueler criminals. He still knows how to steal almost anything, but he has become selective about who deserves to lose it.