As any decent Forgemaster knew, the Golems' greatest weakness was the fact that they were limited to the tactics their maker managed to imbue into their core's array. No matter how talented a mage was, there were only so many situations they could cover without overloading the array.
On the other hand, living beings could learn, could be trained, and most importantly, they could be enslaved. The only problem with Forgemastering living beings had been the mana poisoning that sooner or later would kill them.
Yet by studying the death of countless specimens, the Odi had discovered that when a living being was on the verge of death, their mana would disappear. They had no idea that the phenomenon was due to the cracking and fading of the mana core, nor that it had any relevance to their research.