[11] In addition, divine oracles reportedly informed Cyilima I Rugwe that Nyanguge, wife of mwami Nsoro Bihembe of Bugesera, was the destined queen of Rwanda.

[12] However, Nyanguge was possibly already pregnant when she was sent to Cyilima I Rugwe; the next Rwandan mwami, Kigeli I Mukobanya, was thus widely believed to be the son of Nsoro Bihembe of Bugesera.

[11][13] Various Rwandan legends tell of events relating to Bugesera during the reign of mwami Mibambwe Mutabazi of Rwanda, son of Kigeli I Mukobanya.

[14][12] According to one tale, mwami Nsoro Sangano of Bugesera gave shelter to Prince Mashira of the Nduga kingdom when the latter was conquered by Mibambwe Mutabazi.

[15] According to another Rwandan legend, mwami Mibambwe Mutabazi of Rwanda formed an alliance with Bugesera and Burundi at one point in history to avenge the murder of his mother in "Bunyabungo", an area corresponding to the region west of Lake Kivu.

[8][15] Led by Nsoro Sangano[12] or his successor Muhoza,[15] Bugeseran armies invaded "Bunyabungo" and ravaged the land, killing a local king and taking his pregnant wife as prisoner.

This wife gave birth to a son named Sibula (or "Ntsibura"); when the latter grew up, he was able to return to his homeland, rose to king, and took revenge by killing Rwandan mwami Ndahiro II Cyamatare.

[7] Bugesera's last major ruler was Nsoro Nyabarega who is associated with cave inscriptions as well as oral traditions that are spread over a large area in modern-day Rwanda and Burundi.

[18][6] Some oral traditions claim that the Bugeseran army actually managed to invade Ntare's lands and was only stopped at Mbuye, allowing the Burundians to turn the tide of war.

Mwami Ntare IV of Burundi responded to this crisis by invading Bugesera's southern heartland to capture new cattle and pastures for his realm.

Meanwhile, opportunistic Rwandan herders moved into the remaining Bugeseran territory from the north; they encountered little resistance and were quickly able to seize a substantial area.