I think that it was Moridin that helped Rand in Shadar Logoth. Here's my reasons: 1. Whoever it was, is on the side of the Shadow. Reasons: a)Rand didn't feel him channeling the balefire because he used the True Power. (The headache and double vision is a result of the balefire streams crossing. "Don't cross the streams. I would be bad" -Egon, Ghostbusters) b) He says that s great number of plans will have to be relaid if Rand dies. I think that he is refering to the Dark One's plans for Rand. c) He isn't willing to help Rand kill Sammael. If he were on the side of the Light, one would think that he would help get rid of one of the Forsaken if given the oppertunity. 2. Whoever it is, is high in the Dark One's favor already and not worried about securing a position as Nae'bis. Something that all the Forsaken want, and are worried that Rand will get if he turns to the Shadow. For this reason, they would not mind if Rand were to get himself killed. Rand's helper isn't worried about this. Moridin is definitely high in the Dark One's favor, as evident from the fact that he holds two mindtraps, at least one of which controls one of the forsaken.