BitBallet's avatar
I think its due to a shift from worship to fear. Apparently it was sealed due to its power along with the trio, therefore it might signify the need for humanity to usher in a human-based order that could not exist under the strength (and perhaps primal brutality) of creatures like the Regi's. The key to unlocking the golems in the Ruby-Sapphire series was put in place by these people so that one day they 'might be tamed', which seems to indicate the need for the Regi trio to first be controlled by humanity before they could be awoken. Maybe they became too strong? In the end its all very vague. 
thelakotanoid1's avatar
maybe that might explain his unholy ability slowstart :P and it would be intresting to see this from gigas' perspective