In the end The Theocracy led by God was subdued by being forcibly split into four beings each with their own elemental magic: Nature Elemental, Life Elemental, Space Elemental and Time Elemental. Each of these split beings was contained in a stasis pod around the world. The overall goal is to never get these four beings back together or they will merge once more and resume their bloodshed against technology.
The God is the source of “normal” magic and when they were split in four the magic seemed to have nearly disappeared from the world. The vessels are linked to the God (by extension the four beings) which give the items their power. As the centuries passed the items became gradually weaker due to the waning power inside the element in the stasis pods.
Once the stasis pods are broken, the items slowly return to the original state of power. The vast majority of the magic vessels were destroyed by the survivors of the technological civilization. A few non-living vessels have survived and are used as relics/heirlooms around the world. Most of the towns around the world have one as their prized possession and use them to do menial tasks because they are not aware that they are really tools of war.