Who is Abena and Yao from I, Tituba, Black Witch of Salem and what is their importance?

These characters are Tituba's parents, Abena her biological mother (who conceived her after being raped by a sailor on a slave ship) and Yao her adoptive father (who gave her her name and taught Abena to love her previously resented daughter). Abena is portrayed as strong willed, outspoken and individualistic, while Yao is portrayed as quieter, gentler, and more emotionally flexible. Both characters die early in Tituba's life, Abena as the result of an act of willful resistance to white male power (in other words, she is portrayed as both a martyr and an inspiration). Her execution by hanging simultaneously traumatizes Tituba and foreshadows her own eventual death. Both Abena and Yao continue to be a spiritual presence in Tituba's life after their death, frequently manifesting (Abena more so) when Tituba seeks comfort and/or advice.