In Biggles Hunts Big Game, Kisumo was an operative of the counterfeiting gang led by Kravas. Kisumo was employed at the gang's hunting-lodge at Kudinga where he worked as a hunter/guide for guests who came to the lodge on the "Hunter's Tour", a game-hunting holiday package organised by "Stellar Skyways", the airline operated by the gang.
When Ginger and Bertie arrived at Kudinga on their undercover assignment to penetrate the workings of the counterfeiting gang, Kisumo was assigned as their guide and took them out on a beat the day after their arrival.
Earlier, Ginger and Bertie overhead some of the African employees in conversation and discovered that some of them were actually African-American gangsters masquerading as native Africans. Ginger and Bertie suspected Kisumo might be one of them as well so they tried to get Kisumo to break into American slang but without success.
Ginger next feigned a sprained ankle and asked to be left behind to rest. This worried Kisumo as he was apparently under strict orders not to lose sight of the two of them. Nonetheless, Kisumo was eventually obliged to leave Ginger behind when Bertie moved ahead to pursue a quarry. This left Ginger free to investigate the power house of the camp which guests were told was out of bounds. When Kisumo and Bertie returned from their hunt, Ginger, of course, could not be found. Kisumo, worried about the consequences, insisted that they report the incident at once to Kreeze, the manager of the lodge.
By the time they met Kreeze, Bertie and Ginger's cover was already blown. The gang's network in London had forwarded photos of them outside Scotland Yard. Kreeze sent Bertie out again with Kisumo, ostensibly to search for Ginger. In reality, Kisumo had been given secret orders to kill Bertie.
Kisumo took Bertie to a patch of forest where he then turned around to confront Bertie. This time, he broke into American gangster jargon, confirming Ginger and Bertie's earlier suspicions about him. Kisumo raised his rifle to shoot but he never succeeded in his assignment. Bertie leapt aside, slid and fell. Meanwhile, Ginger (who was nearby but out of sight) shot at an old water buffalo bull who had trapped him up a tree for much of the day. The shot stampeded the buffalo, who dashed away in the direction of Kisumo. Taken by surprise, Kisumo managed two shots at the charging animal. Nonetheless, the mortally wounded bull continued his charge and gored Kisumo to death before succumbing himself.