Dio was the son of the late Dario Brando, a poor thief and drunkard, who poisoned and killed his father out of retaliation for making his mother suffer until she died and found out that his father planned to send him George Joestar I, a member of the upper class who believed Dario to be his rescuer during an accident, in order to raise Dio as if Joestar was his own father if Dario died.
When arriving in the Joestar grounds, Dio immediately tries to assert his dominance and attempts to intimidate George's son, Jonathan Joestar, by kicking aside Jonathan's dog in disgust when it was approaching him during his arrival and manhandles Jonathan after Jonathan attempts to help him with his luggage. He further alienates Jonathan from Jonathan's father and the local boys for the next few days by performing better manners in front of George than Jonathan did while brutally humiliating Jonathan in a local boxing match in front of the local children and started spreading around rumors of Jonathan not being capable of keeping secrets.
After seeing Jonathan being happy with the local girl known as Erina Pendleton, Dio forces Erina to kiss him on the mouth in front of his friends and immediately attacks her after seeing her wash her mouth with mud as if to say that Dio was more disgusting than mud.
Dio is then confronted by Jonathan after Jonathan heard from the local boys what had happened between Dio and Erina. Dio, at first, had the upper hand during the fight but is then overwhelmed by Jonathan by headbutting and throwing several punches towards his face, knocking down Dio. Dio's blood sprays across the room, with some landing on a stone mask, an artifact collected by Jonathan's late mother, hanging on the wall. This causes the mask to grow several rows of curved spikes from behind, making it fall on the floor and catching the interest of the two children.
Dio then proceeds to attempt to attack Jonathan with a hidden knife but is stopped by Jonathan's father, who saw the fight happen and sends both Dio and Jonathan to their rooms.
Several years later, Jonathan and Dio grow up to be excellent students and athletes but the latter still holds a grudge towards the former for what happened in the past and merely pretends to be a good sibling to Jonathan.
However, even years have passed, Dio is still planning on destroying the Joestar family and inherits the legacy of Jonathan's father. Dio plans to poison Jonathan's sick father to death and fakes it as a natural death. He also accidentally finds out the stone mask can transform people into vampires. Unfortunately, Jonathan discovers Dio's evil plan. After Jonathan collects enough evidence, Dio desperately tries to stab Jonathan with his knife and puts on the stone mask at the same time. Jonathan's father died for protecting Jonathan from Dio's knife, and Dio transformed into a vampire after the mask glows out a strange light. Jonathan sets his own house on fire to kill Dio, but Dio still escaped from the house.
Dio then hides in a town and secretly rules the town. However, Jonathan still finds Dio. During this time, Jonathan has learned an ancient martial art technique called the Ripple, he is able to generate powerful energy by special breathing techniques. With this power, Jonathan defeats Dio and destroys his body with only Dio's head left.
Even Dio only has his head left, his vampire cells still let him live. He then follows Jonathan to a ship Jonathan took for his honeymoon trip. Dio commands zombies he created to control the ship and plans to kill Jonathan to take over his body. During his fight with Jonathan, Jonathan accidentally sets the whole ship in the explosion. Which seemingly kills Dio and Jonathan together.
Although the whole ship explodes, Dio still survives by cutting Jonathan's head and attaching his own head on Jonathan's headless body to take over it. Dio then hides in a coffin he brought and sinks into the bottom of the ocean. He waits in the coffin for about 100 years, then a ship salvages the coffin, accidentally bringing Dio back to the civilized world. Dio then hides in Egypt and makes his evil plans to achieve his ultimate goal: rule the whole world and find a way to reach Heaven.
His former enemy Jonathan Joestar's Grandson Joseph Joestar managed to find him and stop his evil plan, along with Joseph's Grandson Jotaro Kujo and other allies. Dio also recruits several Stand Users to assassinate Joseph's team. He successfully killed all Joseph's allies with only Jotaro Kujo and Jean Pierre Polnareff left.
Dio finally meets Jotaro Kujo, but fails in the battle with Jotaro's stand "Star Platinum" and gets wounded severely. At this point, Dio desperately drinks Joseph's blood and nearly kills Joseph. By doing that, his body recovers from all wounds and heals completely. However, Jotaro finds out Dio's stand is a similar type of stand to "Star Platinum", so he gains Dio's Time Stop power and uses it without noticing by Dio. Finally, Jotaro punches "The World" with all his strength-focused, this attack cracked "The World" into pieces, and those wounds reflected on Dio's body. After putting Dio's body under sunlight, Dio's body burns into ashes and ultimately ends his life.
Several years passed after the death of Dio, a friend during his lifetime named Enrico Pucci finds out Dio used to research the ways to reach Heaven and wrote them in his diary. However, after killing Dio in the final battle, Jotaro found Dio's diary and burned it after reading the contents. In order to fulfill his friend's unfinished wish, Pucci sets up Jotaro's daughter Jolyne Kujo in jail to attract Jotaro.
According to Pucci's memory, Dio used to believe that the power of minds and spirits will continue to evolve, and finally reaches Heaven. Heaven is a state that makes people feel the ultimate peace and happiness. This happiness even surpasses the pleasure of gaining supreme power or invincible bodies.
Pucci plans to wait for Jotaro to come and save his daughter, then ambushing Jotaro with his Stand Whitesnake, which has the power to transform people's minds and Stand into DISCs. He successfully gets DISCs from Jotaro and reads the contents of Dio's diary. Then, Pucci finds out Dio's 14 secret words to reach Heaven.
In order to bring Dio back to life, Pucci orders one of his followers with the power to turn dead bodies into zombies to touch a piece of Dio's bone. Dio's bone then turns alive and starts to jump around, touching the 36 criminals Pucci already prepared and locked in a room. All criminals it touched start to become plants and provide energy to this bone. Then, the bone turns into a small and strange kid with green skin, red eyes, and sharp ears. According to Pucci, his kid is named The Green Baby, and he is the manifestation of Dio's soul.
After speaking the 14 secret words to The Green Baby, this strange little thing merges with Pucci's body. This merge shapes a star-shaped mark on Pucci's hair, which looks like the Joestar bloodlines' birthmarks. This process implies that Dio is somehow resurrected and becomes part of Pucci. Pucci's Stand then evolves as C-Moon, with the new power to manipulate directions of gravity. Pucci's body strength also seems improved since he takes a punch from Star Platinum with his flesh body, which might even comparable to Dio himself.
Powers as a vampire
- Superhuman Strength: As a vampire, Dio is much stronger than a normal person. He can punch out a maximum of 2000 kg/cm2 to 4000 kg/cm2 force using his bare fists and is able to jump about 5-6 meters high.
- Superhuman Speed: Stated in the comics, Dio's speed as a vampire is comparable to a leopard.
- Vampirism: As a vampire, Dio can suck other people or animals' blood by teeth, stabbing his finger in their bodies also works.
- Immortal: As a vampire, Dio immunes from aging and illness. He can theoretically live forever if he continuously feeds himself with blood and doesn't get killed intentionally.
- Healing: As a vampire, Dio possesses strong healing power, able to heal from most kinds of wounds. Even parts of his body get detached, Dio can heal by attaching lost parts back. Dio can even live with only a head left, but seems not able to grow a new body in such a condition, and needs to find a new body to merge with. However, if his head gets damaged, it seems like he will be killed properly, or extremely hard to heal.
- Create zombies/vampires: As a vampire, Dio can transform other people or animals into zombies or vampires. Any beings transformed by Dio completely follow Dio's orders.
- Vaporization Freezing Technique: Vaporizing water in his body to freeze things he touches. This technique also freezes Dio's own body, but his healing power helps him get over it quickly. It takes about 2 seconds to completely freeze a man.
- Space Ripper Stingy Eyes: Squeezing liquids in his body and shots them out from his eyes extremely fast to create two pressurized fluid jets, strong enough to cut through stones. Using this technique requires Dio to break his eyes, so theoretically speaking, Dio lost eyesight for a while each time he uses this technique.
- Flesh Buds: Dio's hair can turn into flesh buds and be inserted into other people's brains. People who get inserted by flesh buds will be controlled by Dio, and anyone trying to remove the buds, it will grow tentacles and try to kill both the host and the one trying to remove it.
As a vampire, Dio is almost immortal. However, sunlight and ultraviolet are deadly to vampires. Dio's body will burn into ashes if he is exposed to sunlight, and this process kills Dio definitely. An ancient martial art technique called the Ripple can generate powerful bioenergy by special breathing techniques, and this energy is similar to sunlight. The Ripple energy is also deadly to Dio's body, and it can hurt Dio severely, even enough to kill Dio.
After finds mysterious golden arrows from Egypt, Dio stabs himself with one arrow and becomes a Stand User. Stands are entities generated from people's life energy, each stand has a unique superpower, and people who have abilities to summon stands were called "Stand Users". Dio's stand is named The World, it appears like a strong, muscular man with yellow skin.
As a Stand User, Dio can summon The World whenever he wants or hides it in his body. The World is a close-range Stand, it normally stays about 2 meters from Dio's body after being summoned and seems always floating above the ground, but sometimes it can go further, for maximum 10 meters from Dio's body. The powers of The World are incredible strength, speed, and the power to stop time.
Powers as a stand user
- Superhuman Strength: As a vampire, Dio is already much stronger than a normal person. However, The World even largely surpassed Dio's own physical strength. The World is strong enough to break walls or bent metals. The World can also possess Dio's body to increase Dio's own strength.
- Fast punches: Dio can throw powerful punches with incredible speed that created multiple afterimages. He is able to catch up Jotaro Kujo's fast punches, whose stand Star Platinum is stated to be faster than light.
- Time Stop: The World's real power is to stop time. Dio can stop time for maximum of 9 seconds, only himself can move in the frozen world and interact with other objects freely after he stops the time. Dio often uses this power to get close to opponents when the time stops and assaults opponents. In other people's perspective, it seems like Dio disappears and suddenly appears in another position. Although Dio can only stop time for limited seconds, he can trigger this power again right after one round of time stop ends. Originally Dio can only stop time for about 5 seconds, after his fusion with Jonathan's body becomes better, his time stop power also becomes stronger, allowing him to stop time for maximum 9 seconds. It seems like he can still improve his power.