Moridin was very tall, (as tall as Rand al'Thor), broad-shouldered, and had black hair. He was handsome enough that Moghedien, upon first seeing him, had the thought that only too strong a jaw kept him from looking like someone Graendal might want. He had a deep voice, and eyes that were described as shockingly blue. He was described by Moghedien as appearing to be in his mid-twenties.
The Watcher and the Wanderer
Ishamael was killed by Rand al'Thor in the Stone of Tear shortly after the latter gained possession of Callandor. Unable to draw on enough of the True Power to combat the amount of Saidin that the sword could be used to draw upon, Ishamael was stabbed through the heart by Rand. As the Dark One's most powerful and valued servant, the Dark One immediately captured Ishamael's soul and placed it in a new body. Unlike all of the other members of the Forsaken who were resurrected by the Dark One, Ishamael was not punished in any way for his failure. This was because Ishamael's greatest wish was to die so completely that he would never be spun back into that Pattern. The Dark One knew of this desire, and so he considered returning Ishamael to life to be sufficient punishment.
Shortly after his resurrection, he watched as both Sammael and Graendal spread chaos among the Shaido Aiel. He seemed amused with Sammael's boasting of a truce with Rand al'Thor and that he would be Nae'blis. Moridin was given the title of Nae'blis by the Dark One, effectively naming him his regent on the Day of the Return, the coveted position that set him above the other Forsaken. He was also apparently given virtually unfettered access to the True Power.
Later, he pulled Rand out of a cavern in Shadar Logoth when Rand was fighting Sammael. During this escapade, Moridin shot a beam of balefire at a tendril of Mashadar the same time as Rand did, and the two beams crossed over each other and touched. As a consequence of this, they have formed a connection: Rand then often saw Moridin in his mind when he channeled. The link worked both ways as Moridin was also aware of Rand. The sensation Rand had was of them each touching the other, but not physically. Rand then suffered nausea when he first reached for saidin and, through his link, felt Moridin also suffer the same nausea (this appears to have stopped after Rand's melding with Lews Therin). Moridin seemed to be furious with this apparent side-effect.
He later watched Nynaeve al'Meara, Elayne Trakand, and the rest of their group Travel from Ebou Dar. He became concerned when he found out that they had a ter'angreal that could change the weather back to normal. He was amazed and furious when Aviendha unraveled the weave for her gateway without it exploding.
He controlled Cyndane and Moghedien through the use of cour'souvra, and started to consolidate the power of the Shadow under his command, as he once did as Ba'alzamon. He reluctantly rescinded the order to kill Rand as Rand was planning to cleanse saidin. He ordered Raefar Kisman, Manel Rochaid, Charl Gedwyn, and Peral Torval to take the access keys for the Choedan Kal from Rand. He did not participate in the Battle near Shadar Logoth.
He set up a meeting in Tel'aran'rhiod, which was made to look like the Ansaline Gardens, where he told the other Chosen to leave Rand for him alone. Mat and Perrin were to be found and killed however. He also wanted to find out who was masquerading as Sammael and sent tens of thousands of Trollocs into the Ways. Later he set up a meeting between Mesaana and Demandred, and rewarded Graendal by allowing her to overhear this meeting. During the meeting Graendal spotted that his left hand seemed stiff and causing him pain, the same hand Rand lost recently. He forbade any rescue attempt for Semirhage as her punishment for trying to kill Rand.
While dreaming one night, Rand found himself in one of Moridin's dreamshards, their link to one another having pulled him there without either he or Moridin willing it. Upon seeing Moridin, Rand immediately reasoned that Moridin was the reincarnation of Ishamael, and was angered and horrified to learn that others amongst the Forsaken might have been resurrected as well. However, during a relatively genial chat with Rand, Moridin informed him that the only way to ensure one of the Dark One's servants remained dead was to kill them with balefire. He also expounded slightly on the connection he shared with Rand, though he admitted to not understanding it. The two of them discussed the timelessness of Rand's struggle and Moridin's belief in its ultimate futility. He also revealed that he was feeling exhausted, and wondered out loud whether the exhaustion he felt was Rand's or his own. He also mentioned to Rand that he believed that he knew the truth about the Dark One's intentions - that the Dark One intended to destroy creation forever. He went on to cite his contempt for the other Forsaken, mocking them for believing that they would receive eternal life and power. However, the idea of the end of creation seemed to please him, as he gave a laugh that had "true pleasure in it," as opposed to other, humorless laughs that he had exhibited during the conversation. Before leaving, Moridin asked Rand why Rand had come to his dreamshard, but then speculated that it was their link that somehow drew Rand to it.
When Moridin found Graendal hiding on a desolate island in the Aryth Ocean, he chastised her for her failure and for causing the death of another Chosen. She promised the death of Perrin to redeem herself, and Moridin agreed to allow her to attempt to kill him, loaning her a dreamspike and the services of Slayer. He also showed her a prophecy of the possible death of Perrin. In doing so, he revealed that a chamber within his palace appeared to be full of powerful relics from the Age of Legends. Graendal seemed to have a very difficult time controlling her fear of him during this meeting as opposed to the last time she met with him. She also made an observation that Moridin would understand Rand's feelings of guilt for destroying her lair and its inhabitants, but did not elaborate much. During the meeting it appeared that Moridin was able to receive commands directly from the Dark One without being at Shayol Ghul. Around this time, Moridin's attitude began to attract the attention of some of the other Forsaken as being distinctly different from that of Ishamael. Virtually all of his vindictiveness, cruelty and sadism essentially vanished, and he took to carrying out his tasks in a somewhat mechanical fashion. More often than not he was silent and seemingly detached.
Slayer later spotted Moridin in the Town on some unknown business and recalled when Moridin first entered the Town and obliterated at least a dozen of the Samma N'Sei when they attacked him, not knowing who he was.
The final plan
As the end grew nigh, Moridin gathered the last of the Chosen within one of his dreamshards. Moghedien was given back her cour'souvra with the warning to not fail again, after which Moridin revealed two unfamiliar looking Chosen. One of them was Mazrim Taim, now renamed M'Hael, and the unfamiliar female Chosen present was named Hessalam; Graendal in a new body. At the meeting, Moghedien was placed under Demandred's command, and Moridin gave Demandred overall command of the Shadow's forces at the Last Battle. Moridin then demanded that all other plots and plans by the Chosen were to be concluded and that they were to unite for the Last battle against the forces of the Light. Rand is pulled into Moridin's dreamshard via their connection. Rand reveals that he knows that Lanfear lives again. Moridin tells him that her name is now Cyndane and she now hates Rand. They debate the point to their never-ending cycle of battles. Rand releases his full ta'veren nature and causes sunlight to stream through the clouds and cause all the dying grasslands around to become lush and green again. Moridin can't understand how this happened and flees the dream.
The Last Battle
Moridin then charged the Forsaken to find and kill Mat and Perrin. At the Last Battle itself, he waited with a mortally wounded Alanna Mosvani in the depths of Shayol Ghul for Rand. His eyes are almost completely black from saa. To the side of Moridin is the lifeless body of Shaidar Haran and the black nothingness of the Dark One stretches behind him. Rand arrives and tries to convince Moridin to step aside. Moridin is amused by Rand’s attempt to lure him to the Light. Moridin has been promised oblivion and plans to take it. He rushes Rand and the two of them engage in a swordfight in the now lava-less Pit of Doom. Rand eventually touched this hole with his foot, which froze both of them in place while Rand confronted the Dark One himself outside of reality. When Rand managed to overcome the horrors of the Dark One's assault, Moridin stabbed Alanna in the heart in the hopes Rand would lose control when the holder of his warder bond died. However, Alanna was able to release Rand's bond before she died, so Moridin then stabbed himself in the right hand, knowing that his connection to Rand would cause him to drop Callandor. When Moridin picked up the sword to attack Rand, he realized that it was not only a saidin sa'angreal, but that it could amplify the True Power as well. But when he attempted to use it against Rand, Nynaeve and Moiraine used Callandor's flaw to trap him in a link with them. Wielding Callandor, Moridin was able to draw so much of the True Power that the Dark One was not able to cut off his access to it, and Rand used the link to funnel the True Power, saidar, and saidin, into the Dark One's prison. Using the True Power to shield both halves of the One Power from any attempt by the Dark One to taint them again, Rand combined both halves of the One Power to restore the original integrity of the Dark One's prison.
Dying, Rand managed to bring Moridin out with him as the cave collapsed. They were both moved to the camp by Shayol Ghul for healing. Unbeknownst to everyone at the camp excepting Min, Aviendha and Elayne, Rand used his connection to Moridin to swap bodies, putting Moridin in his own dying body while taking Moridin's body for himself. This was enabled due to the fact that Moridin, above all else, wanted to die, while Rand wanted as badly to continue living. Once the transfer was complete, Moridin died in Rand's body, and was cremated on the Dragon's funeral pyre.
Talents, Personality, Trivia
Upon being reincarnated as Moridin, Ishamael initially kept most of his former personality traits. However, as time passed his personality changed drastically. Though his madness was said to have been even greater as Moridin than as Ishamael, he exhibited a preternatural calm most of the time, and appeared to have left both his pride and his desire for power behind him. Additionally, he lost any hint of sadism that he had once had, and took more often than not to simply brooding in silence. Instead of the fanaticism he had once possessed, he changed to becoming fatalistically devoted to seeing the Dark One triumph, as he believed that his service to the Dark One would grant him his truest desire; to die so completely that he would never have to be reborn again. This desire was brought on by an overwhelming sense of self-loathing, and utter despair regarding what he saw as the inevitability of the Dark One's victory. This desire was apparently so strong that, rather than being punished (both for dying and for impersonating the Dark One) upon resurrection like the other re-incarnated Forsaken, the Dark One deemed that returning Ishamael to life in and of itself was punishment enough. His insanity, therefore, took on an omnicidal tone rather than a power-mad one, as the only thing he wanted was to bring about a permanent end to the world as quickly as possible. However, he did appear to suffer from violent mood swings at times, thought they were very, very transient and he tended to regain control very quickly. Several comments from Graendal suggested that, before his conversion to the Shadow, he may have been much like Rand al'Thor. Indeed, the two of them, even as mortal enemies, appeared to get along oddly well during their numerous conversations in Dreamshards, and before re-integrating Lews Therin's memories with his own and recovering, Rand nearly destroyed the Pattern in a nihilistic despair similar to Ishamael's own.
Ultimately however, despite understanding a great deal about the nature of the Pattern, he ultimately failed to realize the true nature of the Dark One, having believed that the Dark One would have allowed him the peace of oblivion despite the fact that the Dark One was completely incapable of granting peace or rest of any sort.
Apart from being one of the most powerful male channelers - as strong as Lews Therin Telamon - Elan Morin Tedronai was also one of only a few male Dreamwalkers. He used this talent extensively, communicating his orders to Darkfriends via their dreams. He trapped many Darkfriends in Dreamshards to punish their failures, and he also used tel'aran'rhiod to lure the three ta'veren. He also spent much of his leisure time in very subtly twisted Dreamshards. His favorite settings appeared to be realistic places that contained warped or impossible elements. His typical setting involved sitting alone in front of a fireplace that radiated no heat, with disturbingly human-shaped flames and clouds bursting and contorting, and burning rats behind the fireplace. Others involved places like a platform floating on endless water with people chained under the waves, perpetually drowning and being eaten by giant, unseen predators.
As Moridin, Elan was granted essentially unlimited access to the True Power, as Rand al Thor, when drawing on the True Power through his link with Moridin, compared the amount of energy that he was able to draw on as comparable to drawing on both Choedan Kal. His access to this power was so great that, when drawing upon it through Callandor, the Dark One was not able to shut off Moridin's access to it despite being its source.
Brandon Sanderson confirmed on Reddit to a user's question that Rand's and Moridin's soul and body got connected when their Balefire crossed in Shadar Logoth. When it came to swap bodies "The soul that wanted to live found the body that wanted to live, and the soul that wanted to die didn't go to the effort."