* Mea - African girl from the [[Dinka]] tribe, Nel's servant. Shy and quiet, she loves her little mistress and protects her from dangers.
* [[Chamis]] - one of the kidnappers. Earlier a servant of Staś and Nel's fathers.
* - [[Beduin]], one of the Mahdi's followers. Relatively well-behaved towards the children, he admired Staś's courage. He was tasked with bringing the children safely to the Mahdi.
* [[Gebhr]] - the cruel youngest brother of Idris's.
* Mrs. Oliver - Nel's teacher.
* Linde - Swiss explorer, encountered by Staś.
* Smain - husband of Fatma, relative of the Mahdi.
* Caliopuli - [[Greeks|Greek]] worker employed by the Mahdi.
* Nasibu - servant of Linde, after his death he joined with the children on their further journeys.
* Faru - leader of the Samburs, the tribe opposing Kali's tribe.
* M'Kunje and M'Rua - witch-doctors of Wa-Hima, hostile to Kali.
* Doctor Clary - relative of Nel's.
* Captain Glen - met by Staś and Nel in the train.
* Władysław Tarkowski - Staś's widowed father, an engineer.
* George Rawlison - Nel's widowed father, an engineer.
* Fatma - a relative of the Mahdi. Her detention was the reason for the abduction of Staś and Nel.