The Mountain King was the supreme ruler of all dwarfen clans of Thessea (which is essentially all dwarfs, since barely any live in Faraam or Albion). The key word is ALL - the unique feature of the office is that for a clanshead to be elected as the Mountain King, he has to acquire support of every dwarfish clan.
The last Mountain King was Hield Darkensteel, in the Age of Placeholder, who was instrumental in sundering the dwarfen race into Exile and Kharad dwarfs during the Grim Reminder more than 800 years ago. No Mountain King has been elected since then.
The Mountain King enjoys absolute rule over every dwarf of the Realm, no more and no less. He is the source of all dwarfen law and rules by edict, although of course he is himself constrained by the long line of authorities and laws that the dwarfs have created over their history.
The source of this power is, of course, the unanimous consent of all clans to be governed. There were few times when the stars aligned just right for that to happen - for some 800 years of dwarfish history before Grim Reminder, there were only 5 Mountain Kings and none of them ruled consecutively.
The Death Law is the supreme sanction of dwarfen society that only a Mountain King can effect. To breach a Death Law means to transgress against the entire dwarfen race; if it is done by an outsider, by King's will it has to be put to death, whatever the cost. But if such an offence is commited by a dwarf, its fate would be far worse. It would effectively stop being a dwarf, all bonds of kinship, culture and history binding it with his clan and all dwarf - broken in an instant. Once dead (as it sure would be), the name and every trace of the transgressor's existence are erased from dwarfish history - which for a dwarf is fate far worse than death.
But on one occasion was a Death Law broken so massively that there was no earthly way it could be executed. It is hinted at in the Exiles' annals that they becamse such by refusing to follow king Darkensteel's Death Law to abandon their holds and seclude themselves in the depths of mount Kharad. But whether it is true or not is debatable.
Three Death Laws continue in effect to this day. They are as follows:
- To end a Sleeper's slumber by killing him or her or by inaction allowing him or her to perish is a sin unto Death;
- To take up arms against the reigning King in the Kierk and to strike a blow against him, or to maliciously conspire for such a blow to be struck, whether or not it wounds or if the wound is fatal, is a sin unto Death;
- To aid an Elf or an Elf's kingdom, whether by gold, stock or strength of arms, during a state of War therewith is a sin unto Death.
This last Death Law has almost never been invoked - it is a heritage of the dreadful slaughter of Kierk Daergh-Da in the first year of the Elven civil war (to secure the angelskin deposits that were previously traded between dwarfs and united elfs); since then there were barely any wars between elves and dwarfs, sans several dwarfish attempts to retake the keep. However, even though the fires of vengeance have quelled, the cinders still burn deep underneath the ash.