The Choedan Kal are two huge sa'angreal, one attuned to saidar and one attuned to saidin that were constructed during the War of the Shadow to be used against the forces of the Dark One. The amount of Power that could be channeled through these was immense and many believed that it might be sufficient to destroy the world. These were so powerful, that they required additional ter'angreal, known as access keys that appeared as miniature versions of the Choedan Kal.
The use of these was favoured by an influential Aes Sedai named Latra Posae Decume and she was able to persuade the entire female Aes Sedai of the time to support her plan rather than a rival plan by Lews Therin Telamon. The idea was that these would have two functions. Firstly, they would provide sufficient power to drive back the forces of the Shadow, defeating them completely. The second was to seal the Dark One back in his prison permanently. Objections to this were that this sealing would require exact placement, and that the Dark One would still be able to open the bore wider behind the barrier and might even be able to break free in the protected area, at which time, he would be able to destroy the barrier.
This plan was never able to be carried out as the region in which the access keys were being prepared (separate from the sa'angreal themselves due to “uncontrolled resonances during the final stages,”) were over run by the Shadow's forces. The side of the Light still had the sa'angreal, but no safe way to access them; without the ter'angreal it was certain that even the strongest Aes Sedai would be burned out instantly by the huge flow of the One Power. According to Rand (presumably from Lews Therin's memories, the male one at least was only finished after the Dark One's prison was resealed (TFoH, Ch. 6).
The Access Keys
To use the Choedan Kal, which were so large they could not be easily moved, a number of access keys, ter'angreal through which the sa'angreal could be reached, were made. These were lost during the War of the Power and believed destroyed (TSR, Ch. 58; WH, Ch. 13). One of the Access Keys to the female sa'angreal, is in Tanchico, broken, with only the upper half remaining. This was damaged beyond the ability to use. Egwene touches it in tel'aran'rhiod and the Power surged into her then back into the figure and back, causing her great pain with each flash (TSR, Ch. 11).
There were two in Rhuidean, one male and one female. Asmodean and Rand both held the male one and shared the flow of the Power through it. After Asmodean had been defeated and Lanfear had left, Rand collected the female one, a carved white stone figurine perhaps a foot long, lying on its back, a man holding a crystal sphere in one upraised hand (TSR, Ch. 58). Rand takes them with him, first hiding them in Rhuidean (TFoH, Ch. 6) while he attends other business, then collecting them when he decides the time has come to c1eanse the taint (WH, Prologue). He takes them to Nynaeve, with the intention of leaving them in her care until he uses them, but she decides to go with him (WH, Ch. 11). He leaves them with Callandor outside Far Madding, hidden under an inverted weave, and retrieves them after leaving (WH, Ch. 35). The female figure breaks in two, lumpy like bubbled wax where one side has melted. The male figure remained whole (WH, Ch. 35).
The male one, was almost totally encased in Earth, until Galldrian ordered it dug out (TGH, Ch. 20). When Rand comes across it, a hole, at least a hundred paces deep, and ten times as wide had been dug amid hills and farmers fields. Little of the statue could be seen, except for a stone hand, twenty paces across holding a crystal sphere and a dignified stone face, bearded and seeming to hold wisdom and knowledge some distance away (TGH, Ch. 20).
The female one is located in Tremalking, “a stone hand fifty feet high sticking out of a hill, clutching a crystal sphere as big as this vessel” (Bayle Domon, TEotW, Ch. 24). The hand of this one melts, as does the access key used, during the cleansing (KoD, Ch. 23).
Cleansing the Taint
Rand had been told how to cleanse the taint by the Aelfinn when he passed through the doorway in Tear. He initially did not understand their answer as he had been given a riddle in return (TPoD, Ch. 14). According to Herid Fel, the riddle stated “sound principles in both high philosophy and natural philosophy” (TPoD, Ch. 14). Moridin realises what his plan is, though none of the other Forsaken do, most have no idea how it cleansing the taint might even be attempted. Moridin tells them to capture Rand as soon as he starts, or to kill him if need be (WH, Ch. 13).
Rand and the others Travel to a hilltop a couple of miles north of Shadar Logoth and he links with Nynaeve while Cadsuane arranges the rest into groups with various angreal to protect him. He weaves a conduit of saidar, covering distance beyond imagining yet of no length at all, He forces saidin into the weave of saidar and notes a change, a slight shifting and stirring in the foulness. He continues, strengthening the weave of saidar (WH, Ch. 35). As he weaves, he feels it move further and a black dome, a thousand feet in height forms above the city, continuing to grow until it is half a ball, two miles or more high which then collapses in on itself, leaving nothing but a great hole (WH, Ch. 35; CoT, Ch. 19).
Away from Shadar Logoth
The Power being used is felt around the world, outside Ebou Dar (CoT, Ch. 3), in Perrin's camp (CoT, Ch. 8, in Malden (CoT, Ch. 9 and Andor (CoT, Ch. 10; Ch. 11)). When Elayne and Aviendha feel it, Elayne knows it is Rand and wishes to go to him, but Aviendha knows from the ter'angreal in Rhuidean, that this would likely not turn out well (CoT, Ch. 10). Initially, she thinks it is the Forsaken (CoT, Ch. 10, a conclusion shared by the rebel Aes Sedai, who send sisters to the site to read the residues and try and work out what happened. They discover saidin was used and this prompts them to agree to an agreement with the Black Tower (CoT, Ch. 19). In Tremonsien, Barmellin sees the sphere held by the male figure glow, too bright to look at, and in Tremalking, Timna sees the same with the female figure (WH, Ch. 35).
- Main article: Amayar
When Rand cleanses the taint, the crystal held by the figure in Tremalking starts to shine. The Amayar believe that this signifies prophecy and the end of Illusion (WH, Ch. 35). Following this, they started to leave Tremalking for the other Sea Folk islands, where they take poison, committing suicide. They told the Sea Folk who encountered them in time that they had a prophecy about the sa'angreal and that when it melted, it was a sign that it was time to leave “this illusion we call the world” (KoD, Ch. 23).
“A sa'angreal. One of a pair, the two largest ever made that we know of. An odd pair as well. One, still buried on Tremalking can only be used by a woman. This one can only be used by a man...Together they might be powerful enough to Break the World again, perhaps even worse than the first Breaking” (Verin, The Great Hunt, Chapter 31).
“The two must be used in unison to handle enough of the One Power to Break the World...One by itself is powerful enough, but I can think of few women strong enough to survive the flow through the one on Tremalking. The Amyrlin of course. Moiraine, and Elaida. Perhaps one or two others. And three still in training. As for Logain it would take all his strength simply to keep from being burned to a cinder, with nothing left for doing anything” (Verin, The Great Hunt, Chapter 31). Verin's analysis here is almost certainly wrong, given how much stronger Logain is than all the women she mentioned.
“A woman, holding a crystal sphere in one upraised hand, her face calm and dignified and full of wise authority. Whole, she would have been perhaps a foot tall” (Egwene, The Shadow Rising, Chapter 11).
“two great sa'angreal with those together we can challenge...” (Lanfear The Shadow Rising, Chapter 57)
Vaguely Rand was aware of a great, half-buried statue in far-off Cairhien, of the huge crystal sphere in its hand, glowing like the sun, pulsing with the One Power. And the Power in him surged up like all the seas of the world in storm. With this surely he could do anything; surely he could even have Healed that dead child (The Shadow Rising, Chapter 58).
“So that is what he was after. I thought they were all destroyed. Only half remains of the single one I have seen, a fine trap for some unaware Aes Sedai. Keep it certainly. To me it is no more than a figurine” (Lanfear, The Shadow Rising, Chapter 58).
“With those, together we can displace the Great Lord of the Dark himself” (Lanfear, The Shadow Rising, Chapter 58).
If he reached through the huge sa'angreal in Cairhien now, that much of the Power might destroy him (Rand, while tired, The Shadow Rising, Chapter 58).
A foot tall figurine, a robed woman with a serene face, worked in white stone, holding up a clear sphere in one hand (The Shadow Rising, Chapter 58).
“He channeled again, careful not to spring any of his own traps and a piece of the wall vanished, revealing a niche he had carved there. In the little alcove stood two figurines, each in flowing robes and serene of face, and each holding a crystal globe aloft in one hand” (The Fires of Heaven, Chapter 6).
He should destroy them both. Instead he rewove the flows, reset the traps (Rand on the Access Keys, The Fires of Heaven, Chapter 6).
“Could the power of those two huge sa'angreal really be as great as she claimed? That was a direction he did not want his thoughts to take” (Rand, (The Fires of Heaven, Chapter 6).).