Answer: alterego

AnswerCrossword Clue
ALTEREGOA different you
ALTEREGOVery close friend.
ALTEREGOConfidant.
ALTEREGOOther self
ALTEREGOA second self
ALTEREGOPerfect deputy
ALTEREGOTrusted friend
ALTEREGOOther I
ALTEREGOSecond shelf
ALTEREGOMr. Hyde, e.g.
ALTEREGOSidekick
ALTEREGOBruce Wayne, to Batman
ALTEREGOOne of the "three faces of Eve"
ALTEREGOSubstitute
ALTEREGOPerfect substitute
ALTEREGOMr. Hyde, to Dr. Jekyll
ALTEREGOOne's double.
ALTEREGOHolmes to Conan Doyle, e.g.
ALTEREGOTony Clifton, to comic Andy Kaufman
ALTEREGOCaptain Marvel, to Billy Batson
ALTEREGOYou again?
ALTEREGOPee-Wee Herman vis-a-vis Paul Reubens, e.g.
ALTEREGOEvil twin, perhaps
ALTEREGOClark Kent for one
ALTEREGOTony Stark, to Iron Man
ALTEREGOOther side
ALTEREGOMr. Hyde, for one
ALTEREGOZiggy Stardust vis-a-vis David Bowie
ALTEREGOSecond person?
ALTEREGOBosom buddy
ALTEREGODoppelganger
ALTEREGOBruce Wayne, for one
ALTEREGOHyde, to Jekyll
ALTEREGOBatman, for Bruce Wayne
ALTEREGOIntimate confidante
ALTEREGOGreen Hornet, to Britt Reid
ALTEREGOLiterally, "other self"
ALTEREGOOswald Cobblepot, vis- -vis The Penguin
ALTEREGOSuperhero's cover
ALTEREGOBruce Wayne, to Batman, e.g.