Creating a Powerful Curse

[Matrota]

In a 3.5e campaign i'm constructing, a dragon NPC named Erafnir was cursed and permanently turned into a human. I want this to be more than something like the standard permanent polymorph any object, something that the dragon couldn't get fixed by visiting any strong cleric or magician. What are some ways I could create a curse that functions like this? Should it perhaps be tied to an artifact or a deity?

[Shinn]

It really depends on the level of the curse, but if you don't want it to be easily broke, you can tell that every spellcaster (or wand-user) trying to lift that curse would be afflicted by an horrible backslash spell, such as Disjunction or Disintegrate.
Not any spellcaster worth their 2 CP would ever take the risk.

[PacMan2247]

Shinn's got a good idea there. First thing that popped into my head was a variation on geas/quest, forcing the dragon to remain in that form, and do everything in its power to avoid being changed back. Obviously this isn't RAW for the spell, but something that's going to put this over on a dragon to begin with could reasonably be expected to work with epic magic, which could also be used to explain altering the dragon's memory so that it can't even remember what the terms of the geas are (which could be as simple as "Remain in this form and do everything in your power to avoid being changed back.").

[Telonius]

A twin curse. Cast on him: your lover will die (or some other more-permanent-than-death thing will happen) if you tell anyone of these curses. On his lover (unknown to her): if the dragon stops being human, you will die. So, the dragon has to stay human, and can't tell anyone to break her curse first. She doesn't know she's cursed, and shows no outward sign of anything being wrong, so wouldn't know to get herself un-cursed.

[Aharon]

The transformation function of the Wish spell, as described in Savage Species? Even if the same ritual is used to transform back into a dragon, there's some chance the dragon won't regain all his abilities.

[Afgncaap5]

Theoretically, this curse could just be "that hard to break", requiring some sort of plotnium to actually go away. I don't know of many RAW examples outside of Ravenloft, though the book Secrets of Xen'Drik at least seems to have a section giving tacit permission to GMs to do this even if little in the ways of rules are suggested.

It also reminds me of a figure in my own campaign world. He appears to be a humanoid, but his creature type is actually in flux and defaults to aberration. There's a big sword sticking through his chest and to his back; it's a magic sword, meant for slaying dragons. During a fight with a dragonslayer, this entity was stabbed midway through a transformation to human, and the magic sword got stuck. Now if he attempts to shapeshift back, his internal organs would have to pass through the place where the sword is, meaning that turning back to normal would kill him. Attempting to remove the sword also appears to be fatal, and much gold has been spent trying to find a healer who can just get the stupid thing out again so that he can shapeshift back to normal.

In the meantime, he lives as a very successful human merchant. A human who happens to have a really fancy looking sword sticking through him.