Rosyn is a bit of a newcomer to the Magus scene. Her focus and business is mainly focused on the integration of Cold magic with technology and modern convivences... but mainly Ice cream. Machines that make it, Tubs that hold it, and bars in box? It's probably her product.
She's not too prevalent in the lore of Kiki, but she'll probably be the big explainer on how magic works. Since it's mostly her business.