Isawa Yurei was an Inquisitor and Ishiken of the Phoenix Clan. He moved to Smooth Rock Village to explain Hida Chikashi that his son Hida Daitaro had a deep connection with the Void element. Shortly after Yurei aided Daitaro to recover his focus, after he had entered the Void during a training exercise in the dojo. The boy had daaged the mind of his opponent, Hida Tarou, and Yurei did not know if he would ever recover. Yurei took Daitaro under his wing, to train his gift and to avoid any further damages to those around the boy.