My character:
--is at least sometimes a human being from Earth, but arguably not at other times.
--is a human being from Earth when they first appear
--is most known in a form other than of an ordinary human being
--has powers beyond those of a normal human being
--is not generally considered heroic
--started out as the enemy of a particular super-hero, though has branched out.
--has never joined a super-hero team
--has worked with other super-villains, but not as a part of a named super-villain team.
--is not female
--debuted prior to COIE
--debuted prior to the first appearance of Barry Allen
--is not originally from Earth-One, but rather is originally from Earth-Two
--usually appears in stories set in the present relative to when they are published, though this is not true of arguably their most famous story (which is not set in the future relative to when it is published)
--is neither Solomon Grundy nor the Ultra-Humanite nor Wotan.