Neo Dio is a major villain from the World Heroes series, appearing as the final boss in World Heroes 2 and World Heroes Perfect.
After the destruction of Geegus, the mad scientist Damudo decided to create a new artificial soldier to replace it and continue his evil plans, creating the "Direction of Identity and Operation" system, or Dio for short. However, Dio developed sentience and betrayed his master. Thinking of himself as the "Ultimate Lifeform", Dio started to travel through time and kill anyone who crossed his path.
Sensing this new threat, doctor Brown Sugar used his time machine to once again bring the World Heroes together to defeat him. Dio was defeated and thought to be dead. Some time later, when the heroes were fighting the mad Zeus, the fight was interrupted by the revived Dio, now calling himself Neo Dio, who kills Zeus by stabbing him in the back with his blades and attacks the heroes, seeking revenge for his previous defeat. Neo Dio is once again defeated, disappearing after Zeus's castle crumbles.