"Oh that's comparatively easy to answer. It's actually a three piece key, the pieces being hidden: one in Elysium where it is protected from the Evil powers, one in Hades imprisoned away from the Good powers, and the third was sent to the far realms where even the Gods are wary of travelling. And 'key' is perhaps a.. basic description at best. They are keys in the metaphysical sense, less so than the standard sense. One is Magic, One is Science, one is Life... I don't know which is where, just where the three holding places are, and what each key is. To open the Lock, you need the Living key to use the other two at the gate."