Iasius has dark brown hair and blue eyes, and he is quite tall. He is Hylain, so he has pointed ears. He is Leonidas' brother.
He, Keres, and Leonidas appear in a fanfic on this wiki. In that story, he is twenty years old and is already experienced in trade and other things his family makes money off of. He is mostly away from Calatia Village, and most of his time is now in the Capital. Unlike his two brothers and father, he is normally calm and easy-going.
Being Leonidas' brother, he is Link's uncle.