Quackmore Duck (born 1875) is the father of Donald Duck, and has been variously depicted with or without a moustache. His parents are Humperdink and Elvira "Grandma" Duck. He was born in Duckburg, and from and early age displayed a very nasty temper. He worked at his parents' farm till 1902 when he met Hortense McDuck and they became engaged. He started working for her brother Scrooge McDuck.

By 1908 he was helping Hortense and her sister Matilda McDuck run their brother's empire as Scrooge's chief accountant, mainly because Scrooge thought that as a possible heir he would probably work hard and stay honest. In 1920 he finally married Hortense and later in the same year became the father of twins: Donald and Della. So he and Hortense became parents when they already were more than 40 years old, according to Don Rosa.

He remained the chief accountant till 1930 when a fight between Scrooge and his family ended all relationships between them. Quackmore retired and it is believed he died sometimes around 1950, although his exact date of death and death place are still unknown.

More Info: en.wikipedia.org