Mamusu "Rose" Grant is the mother of Peter Grant. She is a light skinned Fula from Sierra Leone, who speaks Krio. Her father had several wives; Alfred Kamara is one of her half-brothers. She has a lot of Temne and Susu relatives. Mamusu went to school in Kambia with a girl named Jo who also lives in London now. Before arriving in England she worked at the library in Freetown with Elsie Winstanley.
When Peter introduced Simone Fitzwilliam to his mother, Rose became furious. She recogniced Simone as a woman who tried to seduce her husband Richard years ago. Since Simone still was young, Rose deduced that Simone was an evil witch.