Broken Dragon

Encounter

Under the Temple of the Devourer there is a chamber where the worshippers have trapped a dragon. Long ago they began the process of sacrificing this dragon to the The Devourer, but found it had it's own regeneration. The dragon became an extra source of regular sacrificial material. However it refused to join them, seeing them as below it, as simple misguided ants. After a century or more of having its organs harvested however, it has lost its mind, becoming more of a simple beast than a great dragon. It's draconic magic still persist, no matter how many times they pull it's Fundamentum out. The magic has been warped by the Devourer, and the dragon's own insanity. The church considers it a holy beast, though acknowledge that it must remain tied up lest it wreak havoc on the church. 
It's Fundamentum is used as a source of magic for the church, though various groups will occasionally steal some of them for use in the creation of magic items.
The dragon is guarded by 6 of the stronger members of the church.