Moro was designed by Toyotarō. He was designed with the intent of appearing as a being of pure evil who the reader could not see as ever becoming good (like King Piccolo). He was based off western demons, specifically goat-like ones.He was also based partially off the grim reaper.
“Moro” is a regional Japanese word for shark cutlet (sometimes topped with soy sauce-boiled vegetables) and is presumably his name origin. Moro’s name may also be a reference to the Canaanite deity Moloch or the personification of impending doom and destruction in Greek mythology named Moros. In Japanese, Moro’s name can also translate as “instruct”.