He is described, by Vlad Taltos, upon meeting him in the Paths of the Dead, with Morrolan e'Drien and Aliera e'Kieron, as being of very tall physical stature, with extremely broad shoulders, dark brown eyes, similarly shaded hair and markedly Dragon facial features. He carries a greatsword.
The e'Kieron line of the House of the Dragon are direct descendants of Kieron himself, and are generally considered the proudest line of House Dragon.
Before the founding of the Empire, Kieron was a leading member in his tribe (namely, the "Dragon Tribe"), which was among sixteen similar tribes of Dragaerans existing in Dragaera at the time. His brother left the tribe for unknown reasons and formed his own small group, nicknamed the "Tribe of Jhereg ", which survived primarily by ravaging and scavenging off other tribes.
Kieron was later able to establish a bargain with the leading member of the "Jhereg Tribe", after uniting the various other tribes under his leadership and preparing for a decisive war with the Easterners. The terms of the bargain were that the Jhereg were to exercise their unique skill in spying and information gathering on the Easterners, and, in return, receive a permanent place in the Empire, in the event the war was won.
Before the historical battle with Easterners, Kieron is said to have had a minor argument with the "Tribe of the Lyorn", over a complication that involved the question of whether to wait for reinforcments from the sea to aid them, as well as issues concerning the formation of the Empire. Kieron claimed the Lyorn could go where they wished, but he and his "Tribe of of all Tribes" would stay and await the arrival of the "Tribe of the Orca".
It is also said that immediately after this argument, Kieron followed a trail that would eventually lead him onto a cliff facing the sea, and stood there, unmoving, for five days (thus the five-day Dragaeran week). The Orca arrived, eventually, but proved relatively useless as fighters on land. Despite this, Kieron won the war, thus laying the foundations of an Empire of Dragaerans.
Kieron remained in the Paths of the Dead after dying, and was never reincarnated.
When Aliera e'Kieron met him there along with her companions, she wanted his greatsword, and received it. Kieron cautioned Aliera not to lose the sword, or else he would come out of the Paths to retrieve it.
See also Speculation:Kieron.