Complex sentence: In 1856 he defeated and killed in battle his younger brother Mbuyazi, Mpande's favorite, at the battle of Ndondakusuka and became the effective ruler of the Zulu people.
Split into simpler sentences: In 1856 he defeated and killed in battle his younger brother Mbuyazi, Mpande's favorite, at the Battle of Ndondakusuka. Following this he became the effective ruler of the Zulu people.