When Kairos was twelve years old, he was told by a creature bound to the crypt beneath the palace that he would die when he turned thirteen. He claims that this was "a great gift", as it freed him to act as he wanted rather than changing himself to fit what other expected of him.
Before Kairos, the previous ruler of the City of Helike was mostly a figurehead, who allowed the nobles and the army to run the city. When the nobility realized that Dorian would be a more active ruler, they offered Kairos the chance to become ruler, expecting him to fall into line like the previous ruler had. This plan was largely successful, leading to Dorian being forced out (and taking to role of Exiled Prince in the process) and Kairos being made ruler.
However, once he had taken power, Kairos began to throw his weight around, and when the nobles objected he fed most of them to his dogs in order to force the rest into line. His thirteenth birthday came and went without his prophesied death. This convinced him that Fate is not ineffable or inescapable, and that he had to power to shape it to his will.
Four years later declared war on Procer, and on the Good members of the Free Cities when they voted to block him from pushing the rest of them into war. After announcing his intention that the Free Cities declare war on Procer, he had the representatives of the Good cities poisoned so that they would die after voting against him.
Kairos is unpredictable, though he seems to plan more carefully than he acts as though he has. On several occasions he expresses disappointment in others, especially the leaders of the other Evil Free Cities, for acting overly pragmatic and not doing things for the fun of it or simply because they can.
He has stated that he considers himself the true champion of the Gods Below, and that the other villains of his time have lost their way. He claims that even if they win victories by their methods, that they are not true victories for Evil because they are not done in the right way.
He also seems to have a peculiar disapproval for swearing. In Helike he has made swearing a stoning offense, and he regularly apologizes for using extremely mild words such as "naughty", despite being in a position of power and acting completely unapologetic of murder and similar actions.
He has an extreme dislike of alcohol, given his father's alchoholism, and has had stocks of it in Hellike siezed and those who protested drowned in their own barrels of wine.
Kairos has dark hair and pale olive-colored skin and isn't much taller than Amadeus. He'll wear a broad grin and one of his hands is usually shaking. One of Kairo's eyes is always bloodshot. After causing deaths, especially in a particularly dramatic and Evil manner, his eye grows redder and his hand stops shaking.   
Friendship with Kairos seems to have less to do with loyalty or charm and more to do with how much someone amuses him. He has taken on Anaxares as a sort of pet, keeping him with him at all times and naming him as an advisor to the crown. According to Anaxares, just being called advisor by a foreign ruler qualifies as 33 counts of treason, or over 50 if you include foreign collusion. He seems to be entertained by Anaxares' calm and lack of obvious fear. Before he died, Kairos admitted genuine respect and admiration at Anaxares' madness and wished him well, even calling the man a friend.
In addition to commanding the loyal armies of the City of Helike, Kairos name grants him many mystical abilities. Despite being extremely young he is able to contend with multiple heroes and villains. He summoned specters to occupy the White Knights band of heroes, he manages to float above the ground when needed, and he can even manipulate a soldier's soul.
The names power stems from the adherence to over the top villainous actions. Whereas most villains try extremely hard to not monologue or be drawn into suicidal stories the Tyrant embraces his villainous nature and seeks to outdo previous warlords of Helike. His name allows him to not only exert influence over his immediate subordinates but to also control structures and to a varying degree the narrative that creation has written.
His first Aspect, Rule, grants him power over any being or force that a villain of his stature could feasibly control, up to and including the local weather (which he used to defeat the army of Atalante).
His second Aspect, Wish, allows him to glimpse the individual motivations of individuals. By learning of an individuals motive it allows him to understand and subvert the mechanization of his enemies. In understanding their end goal he has a better understanding of there current actions as well as crucial information on how to manipulate them. This aspect also allows him to complete his own wishes allowing him to change fate. This provides him the ability to make critical pivots that can drastically change the outcome of a decisive moment. The Skein hinted that using this ability reduces his lifespan, rather than simply expending personal power as most Aspect invocations do. Kairos considers this his favourite Aspect.
- This aspect was able to show Kairos the individual motivations of several individuals, including Catherine Foundling's Peace, Hanno of Arwad's I wish to be just which was twisted with the Seraphim, Cordelia Hasenbach had an implacable Duty, Itima Ifriqui craved Revenge, Masego had a path to Apotheosis steeped in High Arcana, Antigone had a complex wish for Completion, and Archer had a delightfully strange and nuanced Horizon.
His third Aspect, Rend, can cause destruction comparable with Black's Destroy. Kairos has been seen using it to rip open seams between Arcadia and Creation, though use of it exhausts him considerably. Despite the power of this ability it does not destroy but rather causes great harm. It is unable to kill so as to perpetuate the chaos that is the Tyrant of Helike's will.