Dawn Herald was a position held within a Killik nest that was technically that of a warrior and an emissary. They were tasked with the confrontation of the unknown. In addition, they were responsible for uttering the words during the hour of revitalization.
During the Cold War, Vector Hyllus was turned into a Joiner where he became the Dawn Herald of the Killik nest on Oroboro. As a herald, he was more than a typical Joiner and retained a sense of individuality as a result.
They can also go through the Chrysalis of Tranquility: a ritual used to strengthen the Dawn Herald and enhances their link to the universe.