Doppelgänger

A doppelgänger is a person who looks identical to another person. Between Earth One, Earth Two and Earth Three, many people exist in multiple universes, 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