Do you want to compare Supergirl with John Grey? Discover the powers, weakness & weapons of Supergirl and John Grey from Supergirl Biography and John Grey Biography. Find out all about Supergirl and John Grey.# Check out how is Supergirl unique and distinct from John Grey. Discover their love interest, sidekicks, family tree and the movies and games list in which Supergirl and John Grey have appeared. Find out everything about them here!