The Ritual Master and the Scroll Keeper talk about calling the rest of the Skeksis back to the castle. They mention skekSa the Mariner (who first appeared in the manga series "Legends of the Dark Crystal"), skekNa the Slave Master and skekUng the Garthim Master (both from the original film The Dark Crystal (1982)) and skekLi the Satirist (from J.M. Lee's young adult novel "Song of the Dark Crystal"). Oddly enough, skekShod the Treasurer, who appeared in the movie, is not mentioned at all.