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It's strongly implied that Aubin was still alive until less than two decades before the plot began. Yuri says that when he still lived with his mother in western Faerghus, they once took in an old but very wise and kind man. He first taught the young Yuri how to read and write, later saved Yuri's life during a fatal plague, and passed away nearly immediately afterwards due to natural causes.
Aubin is a masculine French given name variant of Albin, from the Roman cognate Albinus, derived from the Latin albus, meaning "white" or "bright".