The talent to enter Tel'aran'rhiod at will, Dreamwalking, is an ability unrelated to the One Power and is found in both channelers and non-channelers. Experienced dreamwalkers also have the ability to enter the dreams of people sleeping. Though doing this is extremely dangerous, placing themselves at the mercy of their subconscious mind. Channelers have the ability to ward their dreams and the dreams of those around them from such invasions. The Forsaken have said such wards can be broken, but the results of such a break is unknown.
Aes Sedai DreamwalkersEdit
In the White Tower, the talent of Dreamwalking is so rare that it considered all but lost, the last Dreamer being Corianin Nedeal. Egwene al'Vere is the Tower's first Dreamwalker in almost five hundred years. With no Aes Sedai to teach her, she was forced to seek the teaching of the Aiel Wise Ones.
Little is known concerning the Forsaken and their connection to the World of Dreams. It is clear that every one of them can enter Tel'aran'rhiod in the flesh through channeling a gateway, but the number of them that can actually dreamwalk is unknown. While Lanfear and a number of others showed the ability to enter other peoples personal dreams, it is not clear if she was present in the flesh. The most is known about the Forsaken Moghedien, she is clearly a full Dreamwalker. Suffering several defeats in the World of Dreams, each time she was found sleeping while in Tel'aran'rhiod.
Just because it is not known who among the Forsaken are Dreamwalkers, does not mean they are helpless in the world of dreams. Each of the Forsaken is extremely familiar and experienced with manipulating Tel'aran'rhiod to their will. Lanfear claims particular authority over Tela'aran'rhiod among the Forsaken, though Moghedien, who is weaker than Lanfear in the waking world, may actually outstrip her there.
Ishamael/Moridin showed to be a proficient dreamwalker. In the first books she lured and endangered Rand, Mat and Perrin in the World of Dreams. Later he met or punished cruelly many Darkfriends in what were his dreamshards.
Mesaana fought her last battle against Egwene in the World of Dreams.
During the Last Battle Graendal/Hessalam damaged severely the forces of the Light lurking in the dreams of the great generals, compelling them to bring their armies to disaster (probably she broke the ward that Aes Sedaai as Siuan put on her Warder Gareth Bryne).
Along with the gift of running with wolves, a Wolfbrother gains the ability to practice a form of Dreamwalking. There are only three Wolfbrothers that we know of; Perrin Aybara has shown a goodly mastery of Tel'aran'rhiod as Young Bull, though Noam, known as Boundless in the Wolf Dream has also shown great facility as a Wolfbrother Dreamwalker. We have no idea how well Elyas Machera, the third Wolfbrother, functions in the Wolf Dream, having never encountered him in that realm.
A Wolfbrother also has the ability to talk and commune with fallen wolves who live on in Tel'aran'rhiod. Though such skills have never been practiced by Dreamwalkers other than Wolfbrothers that we know of with one exception, it seems likely that they also could interact with the fallen wolves were they so disposed. Slayer can. And when she existed in Tel'aran'rhoid Birgitte Silverbow was able to interact with her fellow Heroes of the Horn such as Gaidal Cain when they, too, no longer walked the earth so there is no reason to consider them, or any other visitor to that strange realm unable to interact with wolves if they had any interest in so doing, and if the wolves had any desire to reciprocate the interest.
Later Perrin learned the same ability of Isam/Lord Luc to step in and out in the flesh from the World of Dreams.
The talent for Dreamwalking is not related to channeling, however it is more common in women then it is in men, but is present in both genders.