Daisy Duck
He introduced the Billionaires Club of Duckburg, where Scrooge McDuck is a member, in the story "The Christmas Cha Cha" ("Dell Giant" #26, Nov 1959), written by Gregory and illustrated by Carl Barks. He started doing "Aristocats" stories in the 1970s, when he also penciled most issues of "Daisy and Donald", co-starring Daisy Duck.