The Troika

"Three arrive, and unto three be named Betrayer, Prophet, and Gatekeeper. Seek the Sign of Gha."
  Little is known or understood about the warning in Neferu's Vision in Character Notes (Public) given to him by Trestleblade, who in life had been a deputy at the Ravengro jail. However, the Fellowship soon afterwards met Kyrrn who had an entity named Nyrrk living within her that claimed to be, amongst other things, "the Gate". An Aklo tattoo on her neck, which was learned to indeed be the Sign of Gha, was also translated as “gate”.   Later in Carrion Hill the Fellowship would briefly be reunited with Professor Petros Lorrimor. He too would deliver a warning to Kelath:  
“You must bear witness when the Betrayer reveals his true intentions. For it is only then that the Prophet’s words will ring out, and a terrible choice revealed. Ch’nglui ng nnnogor ot shuggnglui (the Guardian of the Gate) will fulfill its purpose and the Shuggnglui (the Gate) will be made open. The decision made will set the Fate of the living and the dead.” He points to Kyrrn. “She must be present for this choice, or all is lost. Be brave, my Fellowship, for I have been deemed worthy and young Neferu shall return. My time short and, already, I can hear the wings of the whippoorwills. I know you have questions, but alas, my time has run out. Remember, the Carrion Crown is the path.”
  While the identities of the Betrayer and the Prophet are currently unknown, it is now believed that Kyrrn herself is the Gate and Nyrrk is the Key, the Guardian of the Gate, and the Gatekeeper.