Doppelgänger

A doppelgänger is a person who is an alternate universe version of another person. Between each of the fifty-three known Earths, different versions of the same people exist, meaning there are various doppelgängers. Occasionally they may look different, having only once appeared the same.

Unseen doppelgängers
Though at least one of the pair have never been seen, the following characters and their respective equivalents are presumed to be doppelgängers:

Dobles Double astral