The 1980s saw radical revisions of Superman. DC decided to remove the multiverse in a bid to simplify its comics line. This led to the rewriting of the back story of the characters DC published, Superman included. John Byrne rewrote Superman, removing many established conventions and characters from continuity, including Superboy and Supergirl. Byrne also re-established Superman’s adoptive parents, The Kents, as characters. In the previous continuity, the characters had been written as having died early in Superman’s life (about the time of Clark Kent’s graduation from high school).
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