Herein I commit the chronicle of the traveler. Shepherd to the stars in the dark. Though the world be sundered and our souls set adrift, where you walk, my dearest friend, fate shall surely follow. For yours is the Fourteenth seat—the seat of Azem.Emet-Selch
The ancient holding the seat of Azem was known as the traveler, tasked with exploring the larger world and becoming intimate with its myriad peoples and cultures. Azem was friend to Hades, holder of the seat of Emet-Selch, and Hythlodaeus. As a person of action, Azem often would solve problems they encountered without seeking the counsel, or approval, of the other members of the Convocation. This made them somewhat of a headache to their colleagues.
In one such incident, Azem went against the wishes of the Convocation to stop the explosion of a volcano on a tiny island. The Convocation intended to merely watch and acknowledge the event, but Azem intended to harness "Ifrita", a fire spirit concept of Lahabrea's creation, to transform the volcano's aetheric fire safely into the spirit and destroy it elsewhere. Though the reason they give for this to an impressionable Elidibus was the particularly delicious grapes on the island that would be lost otherwise, it is implied that it was to save the livelihood of those who called the island home. Emet-Selch, evaluating the situation, realised that obtaining the concept for Ifrita likely meant Hythlodaeus assisted Azem.
Azem was opposed to the Convocation's plan to sacrifice Elidibus and half of their surviving population to bring forth Zodiark and vacated their position, an act construed by their former allies as 'defection'. They subsequently declined the invitation to join Hydaelyn's summoning. Like the majority of the world, their soul and very being were split into fourteen by the Sundering. As a defector to the cause, the Convocation considered Azem unworthy of having their memories preserved in the constellation crystals the unsundered created. Emet-Selch, however, acted behind the backs of his brethren to create Azem's crystal and imbue it with his friend's signature incantation, the ability to summon allies from far afield.
As the Ascians brought about Rejoinings in an attempt to restore the world to its former form, the disparate fragments of Azem's soul present within the rejoined Shards would merge with the fragment found on the Source. This greater part of their soul would eventually be reincarnated as the Warrior of Light, while the First's fragment would become Ardbert. Ardbert would later merge with the Warrior's without the need for a Rejoining when both souls are united in purpose.
The Warrior of Light came to possess of Azem's soul crystal, which they used to summon allies to aid them in their final battle against Elidibus. Emet-Selch's soul also briefly assists the Warrior thanks to the power of the crystal by rescuing them from the rift between worlds after Elidibus traps them there. The Warrior keeps Azem's crystal afterwards.
Azem shares the appearance of most ancients of Amaurot; taller than any of the races in the current world and wearing a black robe to hide their more distinguishing features. When Emet-Selch glimpses Azem in the Warrior of Light, he sees them without their mask, but the face appears blank to the player. Elidibus later also glimpses the Warrior as Azem, and in this vision they are wearing a black mask. The thirteen other members of the Convocation appear in an Echo vision of Elidibus's inauguration as Emissary, and one member wears what appears to be a black mask, distinct from the red ones worn by their fellows. This black-masked individual is believed to be Azem.
As Azem, they were tasked with traveling the world, becoming intimate with its cultures and people, and identifying the potential threats to the Star to eliminate them. As the seats on the Convocation were given to those best suited for the roles they represent, this implies that Azem had a bit of wanderlust, was generally a helpful person and was gifted in combat. They preferred to solve the problems they were to encounter by their own hand, rather than referring it to their colleagues in the Convocation, and more often than not gathered friends and allies from the local area to assist them.
They appeared to be headstrong and playful, rejecting the Convocation's usual practice of observing events with detached interest—even tragedies—and instead attempting to stop them to preserve, for example, especially tasty fruit. Their perspective was unique and a breath of fresh air, though also frustrating their comrades.
Behind the scenes
The crystals used by the unsundered ancients to raise the shards of their fellows bear the constellations associated with their counterparts in Final Fantasy XII. Azem's crystal, uniquely, doesn't have an associated constellation, rather using the alchemical symbol for the sun, marking their status as a wanderer due to the old belief of the sun traveling between constellations.