Strength and other abilitiesEdit
In the 'WoT Companion' her strength in the power is classified 3(+10), putting three female forsaken above her (Lanfear/Cyndane, Semirhage, and Mesaana) as well as some channelers for the light (Alivia, Sharina Melloy, and Talaan din Gelyn), and on an equivalent level with El'Nynaeve ti al'Meara Mandragoran. But this is in contradiction to what is described in the main books of the saga, where Graendal is described as second only to Lanfear among the female Forsaken. Maybe this is an indicator that Jordan changed his mind about the female Forsaken strength.
Graendal in the Age of Legends was famous as a great psychologist. When she choosed to switch to the Darkness she used her abilities to become a great mind manipulator and became very skilled in the use of Compulsion weaves.
She is beautifully full figured with elaborately curled red-gold hair.
Nindar was a famous psychologist for nearly four hundred years, and was known to heal mental afflictions even the use of the One Power could not cure. She was also a distinct ascetic, living an unadorned life. So fervent were Nindar's beliefs that she thought that all who could not live up to her standards were morally inferior. She thought that the life that most lived was simply too complicated and fast paced. While Nindar was admired by the general public for her ascetic lifestyle, those who knew her well had no love for her since, after all, they could not live up to her standards either.
There is no evidence that Nindar's change of character was influenced by the Shadow, although she was the second of the Forsaken to swear her vows to the Dark One. Rather, it seemed that she realized that the world could and would never live up to her moral standards. Thus, she became the exact opposite of those beliefs, wearing the most fashionable garments and taking the most perverse sensual pleasures. She remembers her first steps towards The Shadow being full of pain.
Her alter ego, Graendal, is a creature of decadence and excess. One of the most physically beautiful women to have ever walked the earth, she habitually wears revealing and seductive clothing and expensive jewelry and keeps only the most attractive men and women near her as her servants. She is very particular about her servants, often choosing former kings and reducing their minds to empty husks. Though she has never led armies for the Shadow, she is well-versed in intrigue and Shadow plotting; her knowledge of the human mind has also led to an unparalleled skill in the use of Compulsion.
After she escaped the Bore, she hid herself in Arad Doman under the disguise of the ailing Lady Basene. She teamed up with Lanfear, Sammael, and Rahvin to try to turn Rand al'Thor to the Shadow. Shortly after Rahvin's death, she secretely murdered Asmodean in Caemlyn Palace, perhaps in a panic at her presence being discovered. Her identity as Asmodean's murderer is left unknown for a long time. It is finally revealed by Shaidar Haran when he blames Graendal for the destruction of three of the Chosen. While he mentioned only Mesaana, it is clear she is also responsible for the deaths of Aran'gar and Asmodean.
She continues her alliance with Sammael, and shows him the Sh'boan and Sh'botay she had captured from Shara hoping to fool him with a red herring. The intention of the subterfuge appears to be to aim, and possibly launch, Sammael directly at Rand, not to hide the activities of the other Chosen. She hopes that Sammael will kill Rand, against the directive of the Great Lord, clearing him out of the way so she can become Nae'blis. Sammael later tricked her into revealing where Mesaana was residing and said that he had made a truce with Rand, in which case he will sit back and watch Rand destroy the rest of the Chosen. She accompanies Sammael when he meets with the Shaido Wise Ones and gives them a callbox. He refers to Graendal in front of them as Maisia, a name that seemed to infuriate her. She helps Sammael disperse the Shaido all over the continent to help spread chaos.
In Arad Doman Edit
Graendal took up residence in Eastern Arad Doman, in a hilly forested area that is within sight of the Mountains of Mist. At Lord Tellean's country manor, she masqueraded as "Lady Basene." When she donned the weaves of disguise as Lady Basene, "her skin became coppery but dull, her hair and eyes dark but flat; she appeared gaunt and frail, a once-beautiful Domani woman slowly losing a battle against illness."
Graendal took advantage of the kidnapping of King Alsalam Saeed Almadar by Elaida's Aes Sedai, and sent out confusing and misleading battle orders to Rodel Ituralde in the king's name. The orders were to do exactly the opposite of what might have ended the war with the Dragonsworn in Arad Doman, thus fulfilling the Dark One's command to "let the Lord of Chaos rule." This is more likely when Ituralde receives an order to offer the Dragonsworn the White Ribbon from Alsalam that we previously saw Graendal sending out via messenger ordered to tell Ituralde that the previous letter-bearer, Lady Tuva, had been killed by a Gray Man.
After Sammael's death, Cyndane and Moghedien are sent to Graendal as messengers. They report that she is no longer a free agent and that she is now under the command of Moridin. After she places both under Compulsion, Shaidar Haran arrives to confirm this. He then tells Graendal that she is braver and wiser than most, and that she can call him Shaidar Haran.
She attends the meeting with the other Chosen in Tel'aran'rhiod, which is made to look like the Ansaline Gardens. There she is told that Rand is not to be harmed and that Matrim Cauthon and Perrin Aybara are to be killed if found. Aran'gar flirts with her and proposes an alliance with her.
Apparent demise Edit
As reward for working so well for the Great Lord she is summoned to Moridin's meeting with Demandred and Mesaana in the Blight. There, Graendal is allowed to hear everything. After the meeting, Moridin hints to her that there will be a place, a promotion for her, subordinate to him but above the rest of the Chosen if she causes Rand great anguish, while not harming him. She must not allow Rand to restore order in Arad Doman. 
Delana Mosalaine and Aran'gar are residing within Natrin's Barrow with Graendal. After Aran'gar's failure in losing control of Egwene al'Vere, she is placed to serve Graendal. Graendal reveals to Aran'gar that the Dark One has begun to favor her and creates a weave of Air formed from the True Power. However, she keeps quiet the fact that it is only a sliver that she can work with. When Ramshalan arrives, Graendal orders Delana and Aran'gar to place Compulsion on him and send him back to Rand. She watches Ramshalan make his way back to Rand and Nynaeve through a special weave that allows her to look through the eyes of a dove. When Nynaeve checks Ramshalan for Compulsion, Graendal then realizes that Ramshalan was bait. She creates a gateway and leaps through, shielding Delana and Aran'gar and leaving them to die. She escapes before al'Thor uses balefire on her fortress out of existence. Ramshalan is now freed of the Compulsion immediately after the balefire struck the fortress. Thinking that Graendal was the one to put Ramshalan under Compulsion, Rand takes this change to be confirmation of her death by balefire. In reality, though, it just indicates that Delana and/or Aran'gar died. It is also revealed that Graendal was the killer of Asmodean.
Graendal portrait by Seamas Gallagher
Graendal retreats into hiding on a desolate island in the Aryth Ocean. Moridin finds her and chastises her for her failure and for causing the death of another Chosen. She attempts to redeem herself by promising the death of Perrin Aybara, which Moridin agrees to allow her to attempt, loaning her a dreamspike and the services of Slayer. However, when Slayer fails to kill Perrin, the blame falls upon Graendal, as Slayer was merely the tool being used by her. Shaidar Haran arrives to punish her for her failure.
Graendal is killed and resurrected for her failure. When she is next seen, she is hideously disfigured and astonishingly ugly; Moridin introduces her as Hessalam, without forgiveness in the Old Tongue, and says her old name is not to be spoken of again.
She has unpleasant features with a hooked and bulbous nose. She has pale eyes which are off-center with each other. Hessalam greatly resents Moridin for her new face.
Moridin gathers the last of the Chosen within one of his dreamshards. Moridin reveals Hessalam a new member of the Chosen, a male who is called M'Hael. Moridin then demands that all other plots and plans by the Chosen are to be concluded and that they are to unite for the Last battle against the forces of the Light.
While Perrin was in the Wolf Dream physically, he sights her manipulating the Great Captains to lead the battles to ruin. However, she noticed him and lashed out in anger, blaming him more than anyone else for her failure. She is later confronted by Aviendha, Amys, Cadsuane, and a handful of other women channelers at Shayol Ghul. Aviendha, enraged at Graendal for killing Rhuarc and making him a tool, attacks her with spears of light and fire. As Aviendha hits her in the side, she travels elsewhere on Shayol Ghul, bringing Aviendha with her.
Exhausted, she manages to shield Aviendha, but not before she ties off a gateway, hoping to signal Amys of her whereabouts. Soon, Graendal drops the shield and they both lay exhausted. As Aviendha begins to pick apart her gateway, Graendal prepares to strike her down with compulsion. In her haste, Aviendha picks the wrong thread, causing the gateway to explode. The explosion is not strong enough to kill either of them, but the broken threads of the gateway hit the weaves for Graendal's compulsion, causing it to backfire on her.
She is shown to worship Aviendha, and is not seen again after having carried Aviendha back to the camp for healing.
The name Graendal may be an allusion to Grendel, one of the three antagonists in the epic poem Beowulf, along with Grendel's mother and the dragon. However the Grendel from Beowulf is a male monster/fighter and bears no resemblance to the Graendal of WoT; rather it is Grendel's mother who's been repeatedly portrayed in film as a shape-shifting seductress more fitting with Graendal's description. However, Graendal's final appearance does have monstrous characteristics, and her monstrosity has already existed on the inside since the day she joined the Shadow.