To be Chosen is to be selected by a Companion to be a Herald, one of the elite guardians of the nation of Valdemar. It is stated that if one is destined to be a Herald than they will often find their way to Haven and to their Companion. If not, then the Companion will go out on Search, often traveling very far away to reach their Chosen. Companions can become violent and agitated if they are denied the right to see their Chosen, as with the Companion Dallen and his Chosen Mags, in Foundation.
Although the exact process of being Chosen is not explicitly described, various Chosen have described the process as feeling as if they were "being weighed and measured," "falling into [the Companion's] blue eyes," or "finding something I didn't know I was missing." This process creates a bond that can affect both the Chosen's and the Companion's mental and spiritual well-being. This bond is almost always permanent and breaking it can cause emotional and mental scarring, depression, and, with few exceptions, suicide.