Ka-zar’s (David Rand) origins are found in the pulps of 1936-37 in a three issue series. His story was serialized in comic form in Marvel Comics #1 (October 1939) running in various forms through Marvel Mystery Comics #27 (January 1942).
After a 23 year hiatus Stan Lee and Jack Kirby reinvented the character (as Lord Robert Plunder) where he made his debut in X-Men #10 (1965). Ka-Zar’s first solo story in Marvel’s Universe was in Marvel Super-Heroes #19 (1969) and continues to pop up occasionally.