The Dark Powers

Having learned more about The Domains of Dread and the forces that guide them, it is reasonable for the party to assume that entities such as Fekre, Khirad, Seriach, Sykane, and Zantras may all be among the mysterious Dark Powers. Clearly, they are not the only ones, given Ismark's corruption.
The following information was curated by your friendly neighbourhood lich at the Amber Temple.

General

The exact nature of the Dark Powers is unknown, even to those of us who study them. What they are, what they want, what their true motivations or alignment are, all remain a mystery, not least because the Dark Powers seem to will it so. Those who communicate with the Dark Powers often find themselves unable to speak about their experiences with others, even in writing, rendering any sort of scholarly consensus on their nature challenging at best.
However, it is known that the Dark Powers are connected to the Domains of Dread, though it seems they are not confined to this space. Though the most common result of a deep bond forged with a Dark Power is the individual connected to that power becoming a Darklord, either of an existing Domain of Dread or forming a new one around them, those with connections to the Dark Powers have been known to wander the realms, doing the bidding of their masters.
Despite their foreboding name, the Dark Powers cannot be written off as definitively forces of evil. Though it’s true that there are countless tales of individuals falling prey to their corruption, doing terrible things both to solidify their pacts and in the wake of them, there are just as many tales of others rejecting the Dark Powers, and being stronger for the experience. There are some Dark Powers who seem openly malevolent, sowing chaos and fear wherever they go, while others may offer gifts that seem on their own neutral, or even positive.
It is also true that their connection to the Domains of Dread, where they seem to be strongest, makes understanding their true nature difficult. The Domains themselves are widely regarded as a place of punishment, each of its Darklords trapped in a hell of their own making, each suffering a curse unique to them, to punish the sins that led to their infamous status. However, as so many innocent or at least neutral parties typically find themselves trapped in Domains of Dread with the Dark Lords, many argue whether the true purpose of the Domains of Dread is to punish the wicked, or simply to torture all within their borders. Whether the Dark Powers are overzealous jailers or simply powerful sadists, none can say, and the Dark Powers seem to glory in their own nebulous reputation.
At the Amber Temple, we have studied the Dark Powers for many long years. Many of us have not survived the process, falling prey to corruption and either suffering the natural consequences or being put down by our peers. Though the naive fall prey to the Dark Powers’ manipulation more readily, they seem to take a particular pleasure in breaking down the defences of those who consider themselves wise, finding just the right pressure points to tempt sages down the path of darkness. Surely it is worth mentioning that though great magical power is required to weaken such creatures and learn their secrets, great magical power also makes for highly desirable targets, and as such, in this as in all things, our greatest strengths are also our greatest weaknesses.
There is no mention of any of the Dark Powers by name. The impression you get is that if anyone has been foolish enough to write down specifics about any of the Dark Powers, the lich is not about to share them with you, lest you succumb to temptation, too.

Breaking a Pact

Though as with all information on the Dark Powers, this information is incomplete, as so many of those who’ve interacted with these entities remain unable to disclose any details, the following has been gathered from what sources have been able to speak.
It is undeniable that once any sort of agreement has been made with a Dark Power, it is exceptionally difficult to back out of that agreement. The same strange compulsion to keep silent with one’s experiences with the Dark Powers seems also to apply to one’s ability to try and disagree with or break faith with a Dark Power. As most people are unable to manage the former, it is no surprise that precious few manage the latter.
The longer that an individual is bound to a Dark Power, the more difficult it becomes to break that tie. In time, inevitably, a connection with a Dark Power will change the person bearing it, sometimes beyond recognition. While some of these manifestations are obvious — disfigurement, strange scents or auras hovering around the individual, compulsions that are noticeably out of the norm — often it is difficult for those around a corrupted individual to realise the corruption has begun until it is already too late. What may begin as a shorter temper, reduced patience, or increased apathy will escalate and, in time, will change the individual drastically.
There is, in most cases, a period of sickness that comes after making a pact with a Dark Power. Usually, this sickness manifests either in the sinuses and respiratory system, in the digestive system, or as a severe headache. The duration of the sickness can vary wildly, with some recovering after only a few days, while others may languish for a week or more. In some cases, an individual may seem to recover completely, only to fall prey to the same symptoms again days or weeks later.
The data available on breaking a pact past this strange physical manifestation of corruption is scarce, because precious few have ever managed such a feat, and even fewer have managed to speak of it after. However, it seems that past the point of sickness, however noble the individual's intentions may have been originally, they will no longer desire to evade their corruption. Whatever path evil has found to their heart is etched into their soul, and as it takes a tremendous force of will on the part of the individual to break such a pact, one must first find a way to make that individual truly willing to even make the attempt. If an individual has strong ties — familial, platonic, romantic, or otherwise — one may employ these ties to try and convince the individual to fight the Dark Power’s influence, but more often than not this path leads only to heartbreak, and sometimes fatalities. Like an addict, the corrupted individual believes they need this connection and power, and moreover that they deserve the power it provides them. Attempts to have their loved ones talk them out of the pact may simply serve to drive them farther from the ties they once held dear.
Some forms of abjuration magic may also help. Repeated uses of a Greater Restoration spell or similar magics may help to purify the soul, and give it the strength it needs to fight back against corruption, but this requires both a cost that many people find prohibitive and a significant amount of time or energy, as well as considerable danger to those attempting to assist the individual in question. While under this therapy, both the individual and their Dark Power will be actively trying to free the individual from the situation that endangers their bond, and neither is liable to worry about killing in the process.
A more feasible course of action for many, though this magic is available to far fewer casters, is the Ceremony spell. Though there is still a material cost associated with the spell, it is far lower than the Greater Restoration spell, and its Atonement function can restore the soul to its original moral compass, allowing for a renewed willingness to fight back against the Dark Power, if indeed that willingness was present in the first place. However, as Ceremony only allows this path to a willing creature, one must first find a way to convince the individual to make the attempt in the first place. The use of spells such as Aura of Purity and Dispel Evil and Good may give a boost to any goodness still lingering in the individual, but are not on their own sufficient to restore their willingness to fight.
Some combination of the above magics and other tactics may be employed to help the individual connect enough with their old self to fight back, but in these cases it is a prolonged, painful, expensive process that ends in tragedy more often than not, either resulting in the death of the corrupted individual or those trying to aid them. The most effective method found so far is divine intervention, but those with a strong enough connection to even attempt such a feat, let alone succeed in it, are exceedingly rare.