Esta é a cena em questão (ênfase minha):
With a sigh, he seated himself on the edge of his bed. The lamps were already lit, more than a dozen, leaving no shadow anywhere. The tent was as bright inside as noonday. “Have you thought over my proposal? Accept, and you walk free. Refuse, I know how to hurt your sort. I can make you scream through endless dying. Forever dying, forever screaming.”
The Wheel of Time, The Great Hunt
Em O Olho do Mundo descobrimos que ele de alguma forma "se fundiu" com Mordeth. Que, além de ser o Cão do Escuro, dá a ele seus poderes não especificados. Além da minha ênfase, não há outra referência de como exatamente Fain consegue subjugar um Myrddraal.
Suportado por esta entrevista (Q4)
Q: In The Great Hunt, who wrote the Dark Prophecy on the dungeon wall in Fal Dara? And why, after Ingtar released Padan Fain from the dungeon, did Fain decide to go to Toman Head? We know he was rebelling against Ishamael's orders (he was supposed to follow the Myrddraal to Shayol Ghul) but why did Fain go to Cairhien and then to Toman Head?
A: Fain (now amalgamated with Mordeth) was seeking his own power base, something he would try again with Pedron Niall and Toram Riatin. He wanted enough power to be able to kill Rand, Mat and Perrin, though most especially Rand, and to protect himself against agents of the Shadow. Because of Darkfriend reports, the Myrddraal who wrote the prophecy already knew who the strangers on Toman Head were, or claimed to be: Artur Hawkwing's armies returned to reclaim the lands stolen from Hawkwing's heirs. He knew that they collared women who could channel, which appealed to Fain/Mordeth, since one disliked Aes Sedai at best and the other purely hated them. The Myrddraal didn't simply give this up to Fain, you understand. Fain is one of the few people who could successfully torture information out of one of the Eyeless. As for why he went to Cairhien first, he knew the location of the Waygate there (along with several others and how to read the guidings in the Ways, this last from Mordeth) and preferred to use the Ways rather than make the longer cross-country journey from Fal Dara to Toman Head.
Eu não acredito que o RJ / BS tenha explicado os poderes especiais de Fain. No entanto, podemos verificar que ele exerce algum tipo de medo sobre os outros Shadowspawn, talvez por causa de sua natureza, sua fusão com Mordeth e o punhal. Nós não sabemos realmente.
Ordeith smiled. It thought him a fool. It would learn. They all would. “First, the matter of, shall we say, agreements and accord?” As he talked, the Myrddraal began to sweat.
Eu li isso como Fain sendo capaz de induzir medo no Myrddraal, (provavelmente) da mesma forma que um Myrddraal induz medo quando olha para as pessoas. Então, novamente, é tudo especulativo. Mas podemos dizer com certeza que seus poderes especiais, pelo menos, o torna capaz de subjugar Myrddraal .