Dragon-Slayers Beware

Question: Can you make a write up of Kur?

Not only can I, but I will! Here's one version of Kur, envisioned as a slain Titan Avatar; his power can easily be scaled down for a large Titanspawn version of the creature instead.

Kur
        Should a traveler choose to bypass the great walled city of Irkallu and continue on through the shades of the Underworld's wastelands, stripped of power from his journey through the gates and with no guide or signpost to point him the way, he might eventually stumble upon a colossal cairn of mighty bolders, striated with age and piled on the bank of the river Khubur where it loops around the Underworld to form its final border. This is the grave of Kur, the great dragon, and it is seldom visited by any living thing.
        Kur was originally one of the myriad brood of Tiamat's monsters, a hideous scaled serpent with many eyes and jaws that stretched wide enough to threaten even the most powerful of gods. A lieutenant in her army, he deserted when it became clear that she was being defeated by Marduk and secreted himself in the Underworld, where none of Marduk's heavenly deities could discover him lurking in the dark primordial waters of Khubur. The neverending stream of human souls into Irkallu, however, grew so boisterous and chaotic that his hiding place was threatened, and he determined to visit the gods as an ambassador to demand that someone take charge of the wreckage.
        The Anunna were not particularly pleased to see the dragon's scaly form slithering into Shamu, but as he approached under the flag of truce and reminded them of his distant relation to him, they had no choice but to treat him with reasonable civility as a guest. Exactly what happened during negotiations that caused him to simply abduct Ereshkigal and drag her down into the depths with him is unknown to any but the ancient gods themselves, but they do not speak of the incident and so far no one has dared ever ask Ereshkigal herself whether or not she went willingly. The ensuing battle between Kur and an infuriated Enki bent on rescuing his granddaughter shook the very foundations of Irkallu and was felt even in the World above, and it was only barely, battered by waves and bludgeoned by the very earth itself, that the god finally stood triumphant. The Titan was buried beneath monolithic stones even he could not lift, and there the dragon has lain, half-dead, for countless years since.
        Kur is, at present, helpless. He cannot escape the enormous burden of his cairn (placed by Ninurta himself, in a feat of Ultimate Strength) and has no control over any events in Irkallu or any realms that might border it. While some of the Anunna, when they bring up the uncomfortable subject at all, claim that he is probably glad to finally be unmolested and peaceful, Kur's fury at the gods for attempting to thwart his plans to impose order on the netherworld has not dimmed with the ages, burning like a slow, vengeful coal in the depths of his serpentine heart. Despite his best efforts, however, there is nothing he can do; at most, a faint tremble is occasionally felt in the streets of Ereshkigal's citadel, the only legacy of his most strident attempts to escape.
        Should anyone remove so much as a single boulder from the weighty pile imprisoning him, however (a feat that would require at least 100 successes on a Strength + Athletics roll), Kur is ready to burst free in all his ancient glory, appearing in his original form as a massive serpentine dragon with slimy, scaled skin, small clawed legs and nightmare jaws capable of swallowing entire buildings whole. The moment the cairn is breached, he will regain control of his ancient haunts as well, causing the river Khubur to immediately flood Irkallu in a rushing tide of his displeasure. Whether or not he would attempt to attack the Underworld is anyone's guess, but it seems likely that he would attempt vengeance against at least Enki, and nowhere outside the walls of the Great City would be safe for long.
        Virtues: Ambition 2, Malice 5, Rapacity 3, Zealotry 2
        Supernatural Powers:
        Avatars: The Beast, The Shaper, The Flood
        Boons: Every one- to eight-dot Boon from every Purview except Guardian and Justice, which are forbidden to him. Kur also has all Boons from the Animal (Snake), Earth and Water purviews and possesses all Boons from the Me (Animal) purview.
        Epic Attributes: Epic Physical Attributes at the 10-dot level (with all appropriate Knacks). All other Epic Attributes at the eight-dot level (with all appropriate Knacks).

Note that this writeup is for Kur as an Avatar of Emamu, as he is one of Tiamat's children, but you could easily use him as an Avatar of Terra or the Drowned Road instead if it works better for your chronicle. You could also take a similar road but set him as a disenfranchised god - after all, Tiamat's children were the grandparents of the Anunna, so he could make a great antagonist or target for PCs to try to redeem in that way as well.