Most people believe death is just a force of nature. A tragic force, but a force nonetheless. They do, however, believe that the Grim Reaper is a harbinger of death. A being who is there to ferry souls to their death.
Death is not a force. He is an intelligent being and a force of nature. When someone dies, Death is there waiting. He is the creator of all things, except magic. Magic is in reality a non-sentient being who created Death to control the universe.
As such Death has control over all things. The elements are given to the Six merely out of curiosity.
While Death is his moniker, no one knows his true name. The appearance he takes is merely in service to the myths of the Grim Reaper. If mortals were to find out the true nature of their religion, the world might collapse.
As such, the enchantments that summon Death are generally summoning the Grim Reaper- a creature Death created. While still formidable, these creatures pale in comparison to the real thing.