From the introduction:
Long ago, in the dawn of galactic history, before the Krikkit Wars decimated the Galaxy, when the Wikkit Gate was forged, there was set up an ancient and distinguished order known as the Guardians Of Time, The Universe And All That Stuff. In every age, the long-forgotten founders decreed, five beings would exist to guard the five elements of the Wikkit Gate, the symbol of the happy utopia that the Galaxy then was. When separated, each of the parts of the Gate was merely a funny-shaped piece of stuff: when joined together, the Gate gave its bearer mystic powers over life, death and the laws of the Universe itself. The five Guardians decided that this was altogether too much of a good thing, and so they decreed that the five elements would be eternally separated until the Universe was ready for beings of such power.