King of Avalonia

This is the highest noble title one can achieve in the island of the same name. There were many kings in these lands, some able to unite under their banner quite the bit of the territory. For that reason, the king of the entire island is sometimes referred to as the High King, to differenciate between them and the other more regional kings of lesser power. Holder of the title King of Avalonia represents the greatest authority and is seen as the ultimate leader of the people. There is no one above them, although some of the more religious people would add "only Icons".
Kings haven't had it easy in the history of this island. Many of them had to be vassals of bigger nations or had problems with foreign raiders. Some were considered too weak to be able to effectively manage the entirety of the country and were therefore just dealt with as just puppets sitting on a throne. The authority has suffered a great damage to its reputation and for a long time, there wasn't much hope that there would be anyone who would be able to unite the quarelling nobles under a single cause.
The new king managed to do that. There are many theories why and equally as many debating wether it will last longer than a generation, the important thing is that the land now stands united again. The High King represents the noble ideals of what a leader should be, however, that ideal needs to be proven in action. King is the defender of the people and their land, he represents justice and therefore is held to much higher standards than any other nobles. If your liege is corrupt, there is no reason to keep him. If he can't take care of his people, there is no reason to feed him either.