Each House assumes the throne and the Orb with a vital energy that allows that House's best attributes to benefit the Empire. But each one has a fatal weakness that in time begins to erode the ability of the Emperor to rule effectively. Then it is time for the Cycle to turn.
The House of the Phoenix signifies both decay and rebirth. As their Reigns progress they become decadent and absorbed in their own interests.
In time, the neglect of a decadent Phoenix Emperor invariably leaves the Empire in a state where only war will rectify the ills. It is then that a Dragon Emperor will assume the throne and set the Empire back in order once more—usually by leading the armies of the Empire into battle.
Under normal circumstances, a Dragon will assume the throne by overthrowing the Reign of a Phoenix Emperor who has grown decadent and neglected the affairs of the Empire to a dangerous degree. The establishment of a Dragon Reign therefore typically ends years of decay and mismanagement, allowing the fighting and organizational skills of the Dragon to benefit the Empire.
Eventually, however, the Dragon becomes over-eager to conquer, and a return to a more traditional, less revolutionary ruler is needed. This is when the Lyorn will take the Orb to curb the enthusiasm of the Dragon for another cycle.
Lyorn Emperors assume the throne at the end of the Dragon Reign. When a Dragon's ambition and arrogance grows too great, a Lyorn Emperor is called for to return the Empire to stability and establish a sense of tradition.
A Lyorn Emperor tends to be a staunch conservative, however, and when faced with a new or unusual problem, a Tiassa's innovation and resourcefulness is needed to assume the throne and guide the Empire.
Tiassa takes the Orb from the House of Lyorn when Lyorn is faced with a problem that conservative tradition cannot counter. It is here that the resourcefulness of the Tiassa pays off for himself, and for the Empire.
In time, however, a Tiassa Emperor's exuberance will run away with him, and his passion will betray him. It is then that a Hawk Emperor is needed to offer a more objective and reasoned approach to the rule of the Empire.
When a Tiassa Emperor has committed an impassioned act that costs him politically — or else costs him his life — a Hawk will take the Orb and attempt to restore reason and order to the Empire.
Eventually, however, the Hawk's detached nature will betray him and make him unable to counter a direct threat. This is when a Dzur is needed to stop thinking about the problem and simply act.
A Dzur will take the Orb when immediate and decisive action is required, which is sometimes beyond the capabilities of a Hawk Emperor.
A Dzur's characteristic temper, however, will eventually spell his doom. Then it is time for the tact and grace of an Issola.
When a Dzur Emperor grows too rash and commits an act that costs him face, or even his life, it is time for the grace of an Issola. An Issola Emperor will attempt to soothe the Court and the Empire after the rash actions of his Dzur predecessor, and lead the Empire with tact and diplomacy.
Eventually, however, a problem or situation will arise that requires more than tact — it will require the ruthless tenacity of a Tsalmoth.
An Issola Emperor will use tact and diplomacy to solve problems that arise during their reign. This can only go so far, however, and eventually a problem comes up that must simply be attacked head-on. This is when the Tsalmoth take the Orb and the rule of the Empire.
This same tenacity can be the undoing of a Tsalmoth emperor, however. Once a Tsalmoth gets so involved in a project or undertaking that he becomes obsessed, he may lose face (or his life) in a way that signals the Cycle has changed, and it is time for a Vallista reign.
A Vallista Emperor takes over from Tsalmoth, presumably once a Tsalmoth emperor has gotten so ahold of an idea that it leads to his destruction (as in the case of Faarith I). A Vallista then tears down the fabric of the former ruler's obsession, and builds something new and beautiful.
Invariably, however, a Vallista ruler engages in great building projects. These can be very expensive, and as a result, Vallista Emperors inevitably attempt to raise tax revenue to pay for these projects. This results in a much stricter application of the laws applying to all taxed activities— which greatly increases the profits of the Jhereg who make their living circumventing these laws. A Vallista Reign is also implied to be somewhat socially-repressive, meaning that common vices are driven underground, to the Jhereg's further profit. All told, this leads to the Reign of the Jhereg.
The Jhereg assume the throne after the rule of a Vallista Emperor, who invariably enforce the tax laws of the Empire to such an extent that the populace becomes weary of it, and supports the Jhereg (whom they would normally shun) in their bid for the throne, as they are seen as the lesser of two evils.
The reign of a Jhereg emperor is, by definition, corruption incarnate. When the populace finally wearies of this situation, (which is made more bearable by the cheap availability of all sorts of sinful pleasures), the House of Iorich steps in to assume the throne, and restore the rule of law.
Iorich assumes the throne after the reign of the corrupt Jhereg. It is up to the house of Iorich to restore the rule of law.
The Iorich's obsessive tenacity eventually plays out, and the application of law devolves into a massive witch-hunt. As the Iorich are essentially incorruptible, they are difficult to dislodge from power when this happens. Only a Chreotha has the ability to trap an Iorich Emperor into having no choice but to abandon power and allow the Cycle to turn.
It falls to the crafty Chreotha to trap an overzealous Iorich Emperor into abandoning power, and allowing the Cycle to change.
Given their insecure nature, however, a Chreotha Emperor is not usually a strong or effective leader, and after a time the Chreotha Emperor becomes easy prey to the machinations of a Yendi who schemes to take the throne for himself and his House.
A devious Yendi will typically put into motion a plot to take the Orb from a Chreotha Emperor. Given the shyness and indecisiveness of a Chreotha, they are typically easy prey to the clever Yendi.
It is given to the predatory nature of the Orca to eventually bring enough power and guile to bear on a Yendi Emperor to force a change in the Cycle.
The Orca's predatory instincts serve them well when it comes time to dislodge an exceptionally devious and crafty Yendi Emperor.
In his turn, the Orca Emperor will turn his attention to gaining wealth and power, preying on the weak and the poor of the Empire. Their tendency to increase the power and prestige of the Imperial Navy will often cause an Orca Emperor to employ the use of Press Gangs. All of this will eventually enrage the peasantry, which, once per cycle, will rise up in a successful revolt and found a Teckla republic.
Like the other sixteen houses, the Teckla do take their turn at ruling, typically after a popular revolution that unseats an Orca emperor. This typically results in the reformation of the Empire into a Republic. It is unclear what happens to the Orb during a Teckla reign, though it is presumably held by the "president" (or whatever the chief executive is called) of the Republic.
Eventually, however, the Cycle must change, and the Teckla Republic will fail, to be replaced by the reformation of the Empire under a Jhegaala Emperor.
Jhegaala stand for change and transformation. It is with this in mind that when their turn to rule comes in the Cycle, they are tasked with transforming the Teckla Republic that precedes them back into an Empire once more.
By the end of a Jhegaala reign, the last traces of the Republic are gone, and it is time for the logical and learned Athyra to take the Orb.
The Athyra take their turn at ruling after the Reign of a Jhegaala. Since the task of putting the Empire back together (after the fall of the earlier Teckla Republic) is complete, an Athyra will look to expand the knowledge and power of the Empire.
It is after an Athyra drifts too far into the arcane to pay attention to the affairs of the Empire that it becomes time for a Phoenix to assume the throne, and take the Orb once more, thus ending one Cycle and beginning another.