WMG / Superman of 2499: The Great Confrontation

The reason there's a single Kent left in the 31st century...

... is that the surviving Els moved to Rokyn after the clan war and only the heir/heiress to the Superman or Supergirl title was allowed to abide in Earth. Alan and Kath had a child, trained him/her for the job and left. Laurel Kent, member of the Legion of Super-Heroes, is their direct descendant.

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