Seto was Ardbert's companion, and during his adventures around the world Seto arouses his sentience. After the world is flooded with light, Ardbert is marked by society as a villain. Seto angry at society for ignoring Ardbert's good deeds prefers to move away and live in Wolekdorf with other amaros.
When the Warrior of Darkness go to Seto in search of the crystal to break the seal of Titania. Seto denies handing over the crystal and offers the Warrior a trial. Once completed, Seto relies on Warrior's resistance to the light. Seto then asks the Warrior to retrieve the locket of his former master who fell into the lake. Receiving the medallion, Seto bestows the crystal and says the Warrior's soul is similar to that of his former master.