~Castle of Wizardry~
Leadership is thrust upon Garion for the first time when Belgarath and Polgara are incapacitated, the former by his battle with Ctuchik and the latter by maintaining a shield to protect the innocent boy Errand, as they escape. Garion destroys the focal point of the power of the Hierarchs of Rak Cthol in retaliation for an attack upon Durnik. With Errand continuously trying to give the Orb of Aldur to everyone in the company (its donation being the source of his name), they return to Ulgo for Ce'Nedra and eventually reach the Isle of the Winds.
At Riva, on his sixteenth birthday, which falls during the Erastide (the winter solstice festival), Belgarion is led by Belgarath, Polgara, and the Voice of the Prophecy to accept the Orb of Aldur from Errand in the Hall of the Rivan King, where the ancient Sword rests above the Rivan Throne. In Garion's hands, the Orb glows with bright blue fire; placing it on the pommel, he is able to grasp the fiery Sword, revealing to all that he is the long-lost heir to the throne. This revelation infuriates Ce'Nedra, because the Accords of Vo Mimbre state that she must submit to the Rivan King on her sixteenth birthday to be betrothed. It is also here that Garion, aided by the Voice of the Prophecy, is able to see each member of the quest for the Orb as the Instruments of Prophecy each had been destined to become.
Shortly after the betrothal, Garion learns from the Mrin and Darine Codex Prophecies that the Rivan King must slay the god Torak or be slain himself. Belgarion, Belgarath and Silk set out on their own to fight Torak, leaving only a note to Polgara and Ce'Nedra with instructions not to pursue them. They sneak off in the night, Garion taking the Sword of the Rivan King with him. Ce'Nedra irrationally assumes she has been jilted by Garion and destroys her apartments within the Citadel, while Polgara knows what the actual reason for the departure is, and causes a titantic thunderstorm overhead.
After much sulking, Ce'Nedra finally learns that Garion has left to meet Torak in a fight to the death. Frightened that she has lost the chance to tell Garion of her true affection for him, Ce'Nedra overhears a conference of the Alorn kings and decides to assist them with their plan to raise an army to distract the Angaraks from Garion's quest so that he may reach Cthol Mishrak safely and destroy Torak.
Ce'Nedra proves herself and lives up to her role in the Prophecy by donning armor and traveling through the cities of Arendia, where she begins giving speeches to the Arends, convincing them to lend their support to the Army of the Overlord of the West. By the time she crosses into Tolnedra, every able-bodied Arend has been inspired to join her army. The book ends with Ce'Nedra, knowing full well that her invasion is a diversion to help Garion, Silk, and Belgarath sneak into Cthol Mishrak and serves no other purpose.
~Enchanters' End Game~
Belgarion, Silk and Belgarath proceed to sneak through Gar og Nadrak, and despite a few incidents (such as being forced to join the Nadrak army at one point), finally reaches the land-bridge and crosses into Mallorea. Despite repeated dreams of temptation by Torak to accept him as a father and Polgara as his true mother, he loudly rejects Torak and manages to reach Cthol Mishrak unchallenged.
Ce'Nedra's plan is less successful. Despite a victory at Thull Mardu, she, Polgara, Durnik, and Errand are captured by Mallorean forces and taken to Kal Zakath, who gives them to Zedar. This is particularly disastrous because Torak wishes for Polgara to be his bride; with the self-confidence her love would give Torak, his strength would become such that the Rivan King would be unable to stop him. Polgara reveals that the Mallorean Prophecies name her as Torak's destined Bride, and that her strength in resisting Torak's call may decide Belgarion's outcome. With Kal Zakath's private armed escort, Polgara, Ce'Nedra, Durnik, Errand, and Zedar reach Cthol Mishrak before Garion, Silk, and Belgarath arrive via the back way.
Inside Cthol Mishrak, Zedar takes his prisoners to Torak's tomb. Garion, Silk, and Belgarath sneak into the iron tower and down a flight of steps, arriving at Torak's the crypt door, where they hear the voices of Zedar and Polgara inside. The three listening outside hear Zedar insult Polgara, then the sounds of Durnik charging Zedar. Belgarath blasts the door open, whereupon Zedar kills Durnik. Belgarath, enraged, seals Zedar alive inside the stone deep in the ground. Torak revives, and attempts to sway Polgara to join him, but Garion sends images of Durnik into her mind, thereby helping her to withstand Torak's call. He then turns to Garion in anger. In the final battle, during which Garion and Torak swell into immensity, a titanic conflict ensues. Garion again rejects the God of Angarak, slaying his corporeal form with the Sword of the Rivan King and thereby vanquishing him forever. Torak, in his final—and most ultimately human—act, cries out "Mother!" as he dies. Belgarath explains that Torak cried out to the universe itself, thereby reaching for the one thing that may have truly loved him.
The gods arrive and take away Torak's body. UL, the father of the gods, agrees to allow Garion to revive Durnik, with the help of the Orb; Mara objects, but relents when Belgarath reveals that there is one Marag left alive. Aldur questions whether Polgara could be so unequally attached to a mortal while she was a Sorceress. Polgara affirms that she loves Durnik and would agree to have no power greater than he has. The gods and Belgarion use the Orb to bring Durnik back to life, but succeed only when Errand places his hand on the Orb.
Upon the company's return to Riva, Garion and Ce'Nedra plan their wedding. Polgara and Durnik are married in a private chapel in the Citadel prior to Belgarion and Ce'Nedra's ceremony in the Hall of the Rivan King. Here, Durnik reveals that he was gifted with the Will and the Word when he was brought back to life, and that Belgarath had been training him to be the Aldur's newest Disciple, thereby fulfilling Polgara's wish that she have no power greater than his own. Ce'Nedra and Garion are married, dance with everyone, and then retire to their chambers.
The story ends with a half-drunk Belgarath, having finally accomplished his eons-old mission, sitting in the darkened Hall of the Rivan King later that night with a tankard of ale, as the glowing blue Orb mysteriously seems to blush pink as Garion and Ce'Nedra enter the royal bed chamber.