I will like to know how can Mzimela have Mnguni sername and Gumende has mnguni to

Luzumana kaMnguni (Royal Lineage)
Son and successor of King Mnguni who continued the royal lineage of the Nguni people. He fathered Malandela kaLuzumana, who would become the progenitor of the Zulu royal clan through his son Zulu.