I would speak wisely human, for you speak as an honored guest, but you speak to one of the Six Conclave Chiefs of the Depen. Think of them like your Jarls, or High Lords, or Princes. Should you upset Chief Brennia's disposition, well, there is no telling what she may order done to you."
The main qualitifaction is to be eligible in the first place, by birth. These six Nouedon families, these tribes, have their own complex hierarchies and methods as to deciding which potential living heir not only gets to exercise their claim when one chief dies, but through these ancient rites and traditions and codified methods they more or less insure bloodless transfers of power. However to explain the methods would potentially take more years than a human has left to live, for the Nouedon, that is the Elves, see the world at a different...pace. A different flow. Succession crises are never a true thing to their people. They have the longevity and commitment that they've come up with a codified process and set of extensive rules for going through one's heirs and blood relatives carefully, with a fine tooth comb, in order and deciding which claim is most legitimate and best for the tribe.
Besides the blood tie to the tribe in question, there are hosts of other things, though again not well known. The Nouedon are a secretive bunch by nature.
Their predecessor must die, of natural causes or in battle, and they must be deemed the heir most suitable with the strongest blood claim amongst those deemed suitable, by the tribal elders. The elders will never meet these individuals, they will not be told names, only the nature of the blood relation, and other relevant information about the legitimacy of the claim, and will make their decision blind. It is forbidden to meet, talk to, or introduce one's self to the tribal elders during this process. This carries a legal standing of disinheritance and up to a century and a half banishment from the Depen for such a crime.
The duties of a Conclave Chief are vast, for they are expected to govern an entire region of the Depen, with their chosen number of trusted advisors and confidantes of course. But ultimately they have absolute power of decision making.
Management and governance of their ancestral homeland, insuring that peace and prosperity, relatively speaking, is maintained. Tax flow, if we are honest, as with all such organizations.
Being a Conclave Chief comes with a host of benefits. This includes the ancestral tribal estate and holdings, a great deal of wealth, power and prestige that can be wielded quite heavy handedly, and even your own small but well trained military force, as each tribe maintains their own standing force outside the Conclave Communal Forces.
Accoutrements & Equipment
Elves being the traditional minded sort they are in many regards, especially on affairs of magick, there are certain expectations of garb and accoutrements if the chief is also a magister, and these traditions are expected to be adhered too strongly. However outside this, a Conclave Chief is their own entity, and as such, does not really have a 'badge' of office universally. It will be a bit different for each tribe.
Grounds for Removal/Dismissal
Barring death, a Conclave Chief cannot be removed, though they can step down should they so desire, in their elder years, though this is more of a hypothetical ideal, since its never happened or been initiated as of yet.
During the Wars of the Depen, to reclaim their homeland, every tribe fought and stood. However after the brutal conflicts, only six remained with enough strength and numbers to truly functionally co-ordinate the revival and recovery of the Depen. As such, the other tribes all split off, each being absorbed into one of the six tribes that now make up the nation that is Depenwood.
The Conclave Chief to a tribe of the Nouedon is...well their leader. Ultimately the person trusted not to know everything. But to organize the tribe, direct resources, listen and learn, weigh the various expertise of all, and guide the tribe accordingly. Many other cultures interpret them as a Lord or Lady, or high ranking nobility, and though this is a fair comparison, this does not mean it is anywhere near accurate. No Conclave Chief in Depenwood's history now or ever has been or could be as disconnected from their people as some other cultures' nobles are from their subjects.
Form of Address
Lord or Lady
Lord or Lady Protectorate, Jarl, High Lord or Lady, that sort of weight and authority.
Source of Authority
They are born into it, and raised more or less with the idea in mind that one day they shall be Conclave chief.
Length of Term