The Prophecy spoke of the Four Fated Souls, Who Would Stop The Unleashing Of The Eight.
They didn't mention Grodak.
He was from the Northern Kingdoms, a mass of pelts and blades who the Warlock Pyromancer paid to hang around and kill anything that got close to him.
The Four didn't think of him as one of them as such, and Grodak didn't seem to think so.
And neither did the Cultists.
So when the Prophesied Final Battle took place, the Cultists failed to wear stab-proof armor.
But maybe because the temple collapse claimed Grodak, that's why he wasn't mentioned?