Large Kaer partners with a dragon prior to the scourge. He is terrified of V------- (that horror whoes name escapse me... Vergergorm?) and thinks that the Kaer is a fairly impressive bit of magic. He is security, they provide respite. They make room for a herd of cattle to feed the dragon along with a sizable portion of the produce they can produce in their magic greenhouse or what the hell ever they build. But the cattle are in much to close quarters, and ventilation is overwhelmed, because frankly no one had ever kept a herd of cattle in a artificial field below the surface of the earth. They become diseased and die off. Effectively locking the citizens in with a starving dragon. He takes over, and forces a lottery system, and begins systematically eating the Kaer's population to survive. He gets by on a starvation diet, and generations of people go by trapped in this nightmare. Then the Kaer opens, and he is left not knowing what to do. to everyone who lives in the Kaer now, it is normal, they all grew up in a diabolical lottery system of being fed to a monster, that's all they know. He of course suspects what Icewing might do, or even Mountain Shadow, if they finds out how he survived. He could slaughter them all, but he knows that any Netharmancer would quickly ascertain what happened if he did so. It was a large Kaer, and certainly the humans had record of its existence, even after all these years. Some one would come calling eventually. He might still be figuring out what the hell to do, and getting the lay of the land. I think he has left and instructed the Kaer to seal it self off for now. His only leeway is that the magic level plateaued, and technically the Kaer might reasonably decided to keep itself sealed for now. But he is desperately trying to find a way to hid his crime. I think it is important that he can shapshift into human form. Not anything he wants, but a specific human body he can take on. I think it's a elementalism spell of some kind, rather than beast master type shapshifting. He walked among his prey. I think he is wracked with guilt, but also feels absolutely justified - humans lives are brief. Asking himself to starve to death so they could live would be like asking a Cathedral to be torn down because sparrows keep flying into the windows and dying in his mind. He also justified that if the Kaer was breached, he could in fact save them, the survivors anyway. He is not really sane anymore. First and foremost a survivor, who found out what he was capable of doing to meet that aim. Now more terror is afoot for the same reason.
Hooks. Bad ideas: PC's could find out about the Kaer, or they could find a spell that wipes the lingering traces of death from an area. But that would be pretty cut and dry, and he would kill them/steal from them and then kill them if at all possible. Better Idea: The Dragon could hire them to do something for him, investigate awareness of unsealed Kaers in barsave perhaps, and it could run afoul. He knows that if anyone dug up any reference to a joint dragon/human kaer it would provoke much interest, and I'm sure he is dying to know if any such information was archived in the great library during the preparatory stages. I figure Kaers are pretty huge feats of magic/engineering, and their preparation was a long and well documented affair- people were certainly planning for the end of the scourge, and wanted to be able to reconnect and rebuild life in barsave, but they also wanted to keep their hands close to their chest as to avoid revealing how to exploit their weaknesses. I'm sure much of the information is cryptic, and has varying degrees of detail. He may have a list of the Kaers architects (who he would have known), and wants to run threw all their known correspondences to see what was revealed privately, these could be in archives all over Barsave. It could start by him killing a still living Elf who was a corespondent with one of the original architects, and stealing his library. (the murder of a hundred year old Elementalist discipline of Upandal would be sure to be news, but a library has to be a valuable thing, and a good cover for a murder. He might go so far to sell the library to the Theran's to cover his tracks.) I think he wants to keep his distance from bardertown, and any of Icewings circle of influence, which prevents him from marching around the great library looking for information about dragons, which would be a huge red flag to icewing. The last thing they want if for the cult of the hunter to get their hands on information about the location of a caged dragon, and all this has occurred to him. I think that is his primary fear, he assumes, correctly, that if Icewing found out, he would slay him. Here is a list of things that have occurred to him, which he is dying to find out:
1: is his Kaer documented in the great library or elsewhere?
2: does Icewing know about it, or is he keeping an eye on it?
3: if not, does Icewing have agents in the various libraries keeping tab on interest about dragons in an effort to maintain radar on the cult of the dragon?
4: do any of the other great dragons in the region have skeletons in their caves, or ambitions, that he can exploit to gain their favor?