Baius
Beaming on him also suggests…perhaps, at the very least, not a weak feeling. As the true father of the crystals, I assume you feel all of them. I had thought that was something special to the High Priest, but now I see it is that they were of your construction. I cannot guess why he feels the light, and you cannot locate its crystal. Only, …….has it always been so chilly in Serenitas? Your winter was fiercer than out own, and Simurgh is not known for temperate winter climes.
Perhaps it is buried underground—buried by magic, I mean. Or in some anti-magic material? That prevents your detection. But I cannot imagine it is in the main body of the cathedral.
Is that enough though? Do you have a map of the…undercity? Do you know how to access that place?