"Malach ha-mavis" is a Yiddish phrase that translates to "Angel of Death." The phrase can also be translated to mean an evil or bad ruler.
Yiddish is a German and Hebrew-based language spoken primarily by the Jewish people. The phrase is referenced in the novel "The Devil's Arithmetic," by Jane Yolen, describing a Jewish girl sent back in time to a death camp during World War II. In the novel, Grandpa Will, who has a five-digit number tattooed on his arm, sees Hannah's arm with a five-digit number handwritten on it. Grandpa Will exclaims, "Malach ha-mavis" upon sight of the number, because it reminds him of Nazi concentration camps, explains GradeSaver.com.