Edgecaller

No, no. Don't be sorry, we are here to learn, and being wrong is the best way to learn.

We know of forgery in the Rose Empire, so it is possible that Captain Zu sought out a Forger, and they made him a Female. From there he could of worldhopped to Roshar, where he became a Radiant. (By the way I am new, and fairly confident that I got something correct)