Moridin and the nae'blis title

[Calen Velervron]

So I know that in the end Moridin was the Naeblis and in charge of all the forces of the dark but I cannot remember if he was the only one to earn that title. Do we ever know what the Naeblis gets to do separate from the other chosen or if anyone else has ever served in the job?

 

[Elania al'Manir]

I went to look in our Tower Library, but the article is super short. It's mentioned in a few other articles though, so I did a little browsing. Although not actually named Nae'blis, Demandred seems like an early favorite for the title. The Dark One asks him if he'd like to be Nae'Blis and then gives him instructions that make him weep tears of joy [LoC: Prologue]. Later in chapter 23 Graendal worries that Sammael might become Nae'Blis because he has a cache of angreal, a truce with Rand, and his attitude is relaxed. Sammael claims to be Nae'Blis to Graendal in CoS chapter 20, although Moridin is watching and doubts that to be true. By PoD chapter 12, Moridin is seen solidly as Nae'Blis when Moghedien and Cyndane visit Graendal to try and make her obey him. In WH chapter 13 Demandred decides to get rid of Moridin, the Nae'Blis.

So basically, I don't think anyone else was ever officially Nae'blis, but Demandred could have been and Sammael claimed to have been as a ploy early on in the series. As far as what the title actually means, the Nae'blis is placed higher than all of the other Forsaken. The only person higher is the Dark One himself. Even Shadar Haran does Moridin's bidding when asked to bring Graendal before him.