Given that Popa is a young single man, middle-aged married man with kids, happily married to the first girl he met, on his third wife and sometimes female it is often thought that he may be an amalgam of created characters. I, however, know the truth. And the truth is this: Popa has invented a time-machine. Popa’s time-machine works by allowing him to cross between various parallel realities at any point in time he chooses. There are just two catches: 1. That he must have an anchor in his original reality and 2. that in each of the parallel realities there is a version of himself that is different, sometimes subtly, sometimes vastly, from his original self. All of the Popa-versions can interact with the anchor in his original world, which just so happens to be the CR. Hence the many Popas who are all one Popa. Or the one Popa who is many Popas. Whichever.
Thing is, though, Popa would not have been able to invent the time-machine without some rather important information that was given to him by his uncle. And I wouldn’t be surprised if his uncle was him…
(With apologies to David Gerrold.)