Reincarnation
Rand al'Thor is special in that he is the only known soul to be woven out by the Wheel of Time for a specific rebirth. Although there are other known cases of rebirth (such as Birgitte Silverbow and Gaidal Cain, and the rest of the legendary heroes), only Rand al'Thor's rebirth has been foreseen. He is the rebirth of Lews Therin Telamon, a male Aes Sedai from the Age of Legends who gained prominence before and during the War of Power as the Dragon, the leader of the Forces of Light against the Shadow during the War of Power. This is why al'Thor is generally known as the Dragon Reborn.
Other evidence is showcased in the prologue to The Eye of the World: Ishamael comments that he and Lews Therin have battled each other since the dawn of mankind countless times, suggesting that the Dragon is a prominent figure every time the War of Power occurs.
Rand hears Lews Therin's voice in his head, something that does not normally occur with reincarnation. In fact, at the end of the 11th novel, Semirhage informs him and those present that Rand is insane, and that his condition is beyond repair and all who have had former lives speaking in their heads have been driven to insanity. However, the Forsaken, including both Semirhage and Ishamael (who was thought to have died) lie habitually so the validity of this statement is uncertain. By the end of The Gathering Storm, Rand seems to come to terms with the voice of Lews Therin, and it is strongly hinted that the voice was simply a result of subconscious rejection of his destiny and inability to come to peace with himself.
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