In the distant past, Kintu was the only person on earth, living alone with his cow. Ggulu, the creator of all things, lived up in heaven with his many children, who occasionally came down to earth to play. On one such occasion, Ggulu's daughter Nambi and some of her brothers encountered Kintu and his cow in Buganda. Nambi instantly took a liking to Kintu and decided to stay and marry him. Her brothers pleaded with her, eventually convincing her to return to heaven with Kintu, to ask for her father's permission for the marriage.
Ggulu was not pleased. In spite of himself, and only on Nambi's persistence and insistence did he bless the marriage on condition Kintu accomplishes a hard task. Ggulu asked Kintu to fetch him water in ekisero (sisal woven basket). Every time kintu tried to fetch water with the basket, it would all spill out through the crevices. Kintu had developed a deep liking for Nambi and really wanted to marry her. He decided to apply dung from his cow below the basket. When the dung dried, Kintu was able to fetch water with the basket without spilling it and Ggulu blessed their Marriage.
Ggulu advised Kintu and Nambi to leave heaven secretly, so that Walumbe, one of Nambi's brothers would not find out about the marriage until they had left. It was feared that Walumbe (which means "that which causes sickness and death") would insist on going with them and bring them misery.
Kintu and Nambi set out for earth the next morning, taking with them the few things that Nambi packed, and her chicken. While they were descending, Nambi remembered that she had forgotten to bring the millet that her chicken would feed on. Kintu tried to persuade her not to return to fetch the millet, but she left him and returned to fetch the millet. On the way back from fetching the millet, she met Walumbe. She did not tell him where she was going, but filled with curiosity, Walumbe insisted on going with her. Kintu and Nambi were therefore forced to go to earth together with Walumbe.
When Kintu and Nambi came to earth, they had children and cultivated crops. Walumbe requested Kintu for one of his children twice to help him with chores at his home. Kintu declined as he had been warned by Ggulu. Walumbe in aggression killed one of Kintu's children. Kintu went to Ggulu and reported Walumbe's actions. Ggulu sent his other son Kayikuuzi(which means "that which shakes the earth") to earth to bring back Walumbe. Kayikuzi found Walumbe but he declined to return to heaven with them without Nambi. Walumbe ran and entered the ground and Kayikuuzi raced after him. It is believed that Kayikuuzi is still looking for Walumbe to date and every time they meet, they fight which causing the earth to shake so much (which explains earthquakes).
Walumbe's presence on earth caused suffering and conflicts. That, according to the legend, is how sickness and death started.