Kevin Plunder's father led an exhibition to Antarctica for a rare element, which they found the jungles of the Savage Land where this "Anti-Metal," later known as Vibranium, was found. When ruthless agents tried steal Lord Plunder's stash of Vibranium, he separated his two children and left for refuge in the Savage Land with his eldest, Kevin. Lord Plunder was killed, however, by natives of the Man-Ape tribe, although Kevin was saved by the sudden appearance of Zabu. Zabu took Kevin with him into the Land of Mists, and the Man-Apes called him Ka-Zar, which means "Son of the Tiger." Ka-Zar grew up in the Land of Mists alongside Zabu, who taught him how to survive.
By the time he was an adult, Ka-Zar had abandoned his former life of privilege for that of a "savage," surviving in the harsh Savage Land. His brother, who called himself Parnival the Plunderer, finally found his brother and fought Ka-Zar for his half of their father's "key." The key would serve as a catalyst to activate the Vibranium's properties of "melting" other metals in its area. Ka-Zar eventually regained his knowledge of his British upbringing, acting like "an irreverent Americanized adventurer." Staying in the Savage Land as its self-proclaimed protector, Ka-Zar had many adventures and teamed up with many super heroes. He later met and married Shanna The She-Devil, and more recently, they had a son, Matthew.
Ka-Zar and Shanna only left the Savage Land for a brief time when the two were rescued by the Avengers after a giant alien Terminus succeeded in destroying the Savage Land. They wandered the world, but later found the Savage Land regenerating itself and returned. They were on hand to aid such friends as the X-Men; Magneto, who confronted Zaladane and her Savage Land Mutates; and the Sub-Mariner, who fought various corporations from excavating the Land's resources. More recently, Ka-Zar and Shanna left the Savage Land again to pursue Parnival the Plunderer, who stole alien technology that enabled the Savage Land to maintain its environment. They ultimately defeated Parnival and his master, the cosmic Titan, Thanos.
Ka-Zar remains protector of the Savage Land.