The Black Nun was a member of a religious order worked in the hospital in Port-Gentil, French Equatorial Africa (modern-day Gabon) during World War I. She tended to the medical and spiritual needs of the patients and visitors. Her colleagues included the White Nun, and the Army Doctor and 2nd Army Doctor.
In late December 1916 or early January 1917, she and the White Nun were checking on patients and found a group of Belgian officers and soldiers, including Captain Henri Defense (Indiana Jones), Lt. Baudouin, and Privates Zimu and Juba, with an Ubangi orphan, visiting their comrade, Sergeant Barthélèmy, who had recently died of a gunshot wound. While her partner was concerned with giving proper respect to the deceased, the black nun took an interest in the boy, asking if Barthélèmy was the father. Jones replied that Barthélèmy was the boy's friend, and now the boy was alone. When Jones inquired if she spoke Ubangi, she responded that she did, and translated a message to the boy from Jones, reminding him of the words that Barthélèmy had tried to instill in the child - to grow up strong and wise and make his people proud. Seeing that the soldiers were not able to care properly for the boy, she offered to take the child, and they bid farewell to the child before handing him over to her.
Given that she worked with patients in the hospital, it is likely that she had some basic education in nursing, as well as her role as a member of a Catholic order of nuns.