One of his military camps, known as "Iziruguru", was attacked by a people called "Abanyabungo" from the western Kivu in the modern-day Congo.
Kigeli II attacked chiefdoms in eastern Congo, including Bishugi, Kamuronsi, Gishali, Buhunde, Buzi, and Tongo (Masisi).
During Kigeli II Nyamuheshera's reign, parts of Rwanda were under occupation by neighboring kingdoms.
Kigeli II's opportunity to attack and reclaim Bwanacyambwe and Gisaka arose when the teenage king of Ndorwa, Gahaya I Rutindageli, initiated a conflict against his cousin, the teenage king of Gisaka, Kimenyi III Rwahasha.
Ndorwa's queen mother, Nyiragahaya I, went to war against Nyirakimenyi III Kabonde of Gisaka on behalf of their sons.
Kigeli II agreed on condition that King Kimenyi return the territory of Bwanacyambwe to the Kingdom of Rwanda.
The Ndorwa army was defeated on the first attack and the Kingdom of Rwanda regained its territory of Bwanacyambwe.