When Superman's son Joel was rendered powerless by an attack by Lex Luthor when he was only an embryo he tried to be a hero in other ways and fought in Vietnam. There Joel fathered a son with a Vietnamese woman named Mei-Lai before he died as pawn in one of Lex Luthor's schemes. Mei-Lai  married Bruce Wayne's son BJ (the new Batman) and BJ adopted her son. Named Clark, the young man fought by his adoptive father's side as Robin. When BJ prepared to make Clark the new Batman, Clark instead made a new identity as Knightwing, as only a Wayne should be Batman (and he learned on his own that his father wasn't BJ). Knightwing later met his grandfather Superman, who used a serum to activate Knightwing's Kryptonian genes and gave Knightwing all of  Superman's powers (at 1/4th the strength). Later Knightwing would assume his grandfather's role as Superman, and fathered two girls Lois and Lara who became Supergirl Red and Supergirl Blue. A kyrptonite explosion killed Clark and Lois, leaving Lara to carry on her family's heroic legacy.