Asteroid K-19 is rumored site of unsanctioned fighting tournaments. Long a rumor in the criminal underworld, the asteroid exists and is known of by the Legion of Superheroes. Participants are required to have super powers and fight opponents until they are defeated and then replaced by the new champion as decided by the K-19 Referee .
Karate Kid attempted to enlist in the tournament but was rejected when it was discovered he had no super powers. Around the same time, Superman and Chameleon Boy arrived in disguise to recruit for the Legion. Superman was undefeated until he encountered Karate Kid. Sensing a kindred spirit, Superman acknowledged Karate Kid's victory and offered him membership.
- K-19 Referee
- Karate Kid (Contestant)
- Superman (Contestant)
- The Karate Kid