Many of Moorcock's novels and short stories take place in a shared Multiverse: an array of interconnected parallel universes, many-layered dimensions, spheres, and alternative worlds, spanning from the Big Bang to the End of Time and from planet Earth to faraway galaxies.
The Eternal Champion is an appointed paladin of Balance who is bound to exist in each and every world and age of the Multiverse, so that Law and Chaos are perpetually kept in check; however, he often does not know of his role or struggles against it, never to succeed.
Since he must intervene whenever either Law or Chaos has gained an excess of power, requiring him to tip the scales accordingly, he is always doomed to be surrounded by strife and destruction, although he may go through long periods of relative quiet.
It is also worth mentioning that the first edition of the Second Ether trilogy was published by Millenium itself right after "The Tale of the Eternal Champion" was completed, and that while Jerry Cornelius's and Karl Glogauer's novels were not formally included in the series, nonetheless they were still being distributed in the UK by Orion under its Phoenix House imprint, together with Moorcock's non-Champion novels Gloriana; or, the Unfulfill'd Queen and The Brothel in Rosenstrasse.
As a result, Jerry Cornell's duology was the only series in the Eternal Champion mythos not to be included in either collection, nor officially nor informally.