Of all the topics in Valdemar fandom, perhaps the most discussed is that of a companion's choice. Just why do the companions choose particular people over others? What qualities do they have that make them ideal Herald-candidates? Even the people of Valdemar believe that it takes an exceptional person.
Gender and Sexual Orientation
These are both unimportant to a companion and have nothing to do with his or her choice. There tends to be more boys chosen than girls (Arrows of the Queen p104). There have been several same-sex herald couples, including Vanyel and Tylendel, Ylsa and Keren, etc.
Age
A companion usually chooses a young child on the cusp of puberty, as this is the point in the child's life when gifts manifest themselves. It is an ideal age to be chosen, as the child should already have a good grasp of basic education (reading and writing) and yet is still young enough to be trained in the disciplines required to be a Herald. However, there are exceptions to this rule. Malken, in Brightly Burning, was chosen at a very young age, as the early manifestation of his gift required the stabilising influence of a companion. In A Child's Adventures (Sword of Ice) an elderly grandmother is chosen - in her case it was her wisdom and experience that was sought after.
Capability
The person chosen must be up to the task of learning all that is required to become a Herald. The training is quite rigorous, both mentally and physically. They needn't be a genius - most are of average intelligence - and fitness can be acquired. However, the person chosen is preferably of sound mind and limb.
Social Status
Heralds have a unique place in society, accepted by all and yet part of no social strata but their own. There is an interesting difference of opinions about a Herald's status. Vanyel's father, Lord Withen Ashkevron asked "And what does some damned lowborn Herald know about fighting?" (Magics Pawn p18) indicating the belief among many nobles that they are higher ranked than Heralds. The contravening viewpoint is held by the poor, as indicated by the thief, Skif, when he asserts "Heralds are - well, they're all noble an' higborn - " (Take a Thief p267). His companion Cymry answers the question, stating that no more than a quarter are of high rank and the rest are ordinary people such as farmers. A companion does not care about status or rank of their chosen; they are looking for other qualities. Cymry also goes on to say: "There wasn't anything special about them [heralds] until then - not visibly anyway." So what is this 'invisible' quality?
Character
The Herald's character is very important. They must be innately good people, even though they may not have had a chance to express the good side of their nature before. They must be reedemable from whatever past misfortunes have befallen them. Dean Elcarth makes this note of Talia when she first arrives at Haven: "she may have had her spirit bent but it wasn't broken; Rolan would never have chosen her otherwise" (Arrows of the Queen p77)
Allegiance
A companion will only choose a person that can devote themselves entirely to being a Herald. There can be no conflict of interest. Healers and bards are too busy being healers and bards to be chosen, and they are needed where they are. The sole heir to an estate cannot be replaced, nor can the breadwinner of a family. A priest is commited to his diety. The tayledras are bound to the land. They have prior commitments which could interfere with their heraldic duties (as Tylendel's did in Magic's Pawn).
Gifts
Finally, there are the all-important gifts. A person can meet all the criteria above but if they have no gift they will not be chosen. Gifts are what set Heralds apart and enable them to do their duty.