A Multiversal Wavefront

Poul Anderson refers to Old Wilwidh on Merseia. Jerry Pournelle and SM Stirling refer to Old Kzin. We think of Old England. Evocative language. The use of this adjective with a capital initial conveys that its hearers or readers are aware of history, time and change.

One pocket universe comprises the Old Phoenix. Another might be a control room where an observer monitoring screens and instruments detects a multiversal wavefront with details manifesting alternately as Martians, Merseians, Moties, kzinti etc. Multi-dimensional patterns emerge. A Solar Commonwealth morphs into a CoDominium, each succeeded by a different First Empire:

"'Those two worlds - and many more, for all I know - are in some way the same. The same fight was being waged, here the Nazis and there the Middle World, but in both places, Chaos against Law, something old and wild and blind at war with man and the works of man. In both worlds it was the time of need for Denmark and France. So Ogier came forth in both of them, as he must.'"
-Poul Anderson, Three Hearts And Three Lions (London, 1977), p. 155.

The observer in my hypothetical control room must dispatch agents to crucial moments where they intervene to prevent inter-cosmic chaos. Although the observer knows of a single timeline protected by a Time Patrol, he oversees multiple timelines.

"'Once the crisis was past in both worlds, the job done...well, equilibrium had been re-established. There was no unbalanced force to send me across space-time. So I stayed.'" (ibid.)

Our history does not record Ogier opposing the Nazis - or the Merseians, kzinti etc - but what might occur without our knowledge?