Nyamiyonga is the king of the underworld. There were three royal dynasties—first, the shadowy Tembuzi, of whom Kakama was the first and Isaza the last; second, the Chwezi, part-legendary hero-gods whose marvelous exploits are still spoken of; and third, the Bito, the line to which the present king belongs. Myths link these three dynasties together into a single line of descent, creating an unbroken chain between the present ruler and the very first king of Bunyoro.
A story tells how Nyamiyonga, the king of the underworld, sent a message to King Isaza, asking him to enter a blood pact with him. Isaza's councillors advised against this, so Isaza had the pact made on Nyamiyonga's behalf with his chief minister, a commoner called Bukuku. When Nyamiyonga discovered that he had been united in the blood pact with a commoner, he was angry, and he determined to get Isaza into his power. So he sent his beautiful daughter, Nyamata, to Isaza's court, where she so attracted the king that, not knowing who she was, he married her. But he resisted all her efforts to persuade him to visit her home, for he could not bear to be parted from his cattle, which he loved more than anything else. Nyamiyonga thought of another plan. He caused two of his most handsome cattle to be discovered near Isaza's kraal, and these were taken to the king, who soon loved them most of all his herd. One day they disappeared, and the distracted Isaza went in search of them, leaving Bukuku to rule the kingdom in his absence. After much wandering, Isaza arrived in the country of spirits, where he found his two cattle and also his wife, Nyamata, who had gone home some time previously to bear him a child. Nyamiyonga welcomed the Nyoro king, but he had not forgiven him, and he never allowed him to return to the world of men. In due course, Nyamata's child was born and was named Isimbwa. See also: Ndahura, Ruhanga, Wamara.