Serin is a character from Secret of Mana. He was once the guardian Mana Knight who protected the Mana Tree from evil. However, in his last battle against the Emperor Vandole, he fell near the village of Potos and was never seen again. When Randi fell from the waterfall, he used his last moments to guide Randi to the Mana Sword and remove it from the stone where it was resting, but faded away before he could explain the purpose of this act.
Serin is Randi's father, who was ambushed by Thanatos and killed (near Potos).