I didn't realize there was a write-up for the creation of the ulgurstasta. So I made my own, by writing out the apostelic scrolls (which the PCs found last week).
I'm playing a Forgotten Realms conversion of AoW, in which Ekaym Smallcask (the noble who hires the PCs) becomes Lord Urtos Phylund II. He has a different hook to Loris Raknian (Pendergast Brokengulf IMC). Urtos' late father was murdered by his new wife, who married Pendergast Brokengulf shortly after becoming a widow.
My PCs also travelled with Mélinde, the female paladin from Diamond Lake (Leilon IMC), for most of their adventures. When they were taken captive in Hall of Harsh Reflections, Bozal Zahol showed up and took Mélinde with him, mumbling something about a righteous heart.
Last session the PCs found Mélinde's body - with her heart missing - and the empty coffin of Lord Urtos I. In the altar room the stumbled upon the Apostelic scrolls, with the heart and the bones of Lord Urtos next to them.
Although the sphere of force prevented the PCs from taking the scrolls, they could read them. I made up a ritual in which a worm of Kyuss is nurtured to a full ulgurstasta over a couple of months by unholy worship and sacrifice. Some of the ingredients are the 'bones of innocence murdered' and the 'heart of righteousness'. Of course, the final ingredient is still missing, the 'blood of the champion'.
I'd post my scroll text here, but since it is written in Dutch, I'm afraid it won't do you much good.