Dio Brando , later known mononymously only as Dio , is a fictional character and the main antagonist of the Japanese manga series JoJo's Bizarre Adventure written and illustrated by Hirohiko Araki. He is featured initially as the main antagonist of the series' first part, Phantom Blood, and later returns as the main antagonist of the series' third part, Stardust Crusaders, now solely referred to as Dio. In the alternate universe of the series' seventh part, Steel Ball Run, a character named Diego Brando bears resemblance to Dio and appears as a major antagonist.

JoJo's Bizarre Adventure is a Japanese manga series written and illustrated by Hirohiko Araki. It was originally serialized in Shueisha's shōnen manga magazine Weekly Shōnen Jump from 1987 to 2004, and was transferred to the monthly seinen manga magazine Ultra Jump in 2005. The series is divided into a total of nine story arcs, each following a new protagonist bearing the "JoJo" nickname. JoJo's Bizarre Adventure is the largest ongoing manga series published by Shueisha by number of volumes, with its chapters collected in 134 tankōbon volumes as of April 2024.