|“||He IS PURE EVIL, right down to his very bones! Is he a victim of circumstance, you're wondering? Not on your life! He's been evil since he drew his first breath!||”|
—Speedwagon, giving Jonathan his assessment on Dio
Dio was born the son of Dario Brando, an alcoholic and abusive father who he secretly despised—in part for having caused pain to his mother. It influenced Dio to covertly murder his father with a poison he secured from Wang Chan, learning from his dying father of George Joestar's debt while told take advantage and seize the Joestar fortune.
Once in the Joestar Mansion, Dio wasted no time passing himself as a model gentleman while tormenting his new adoptive brother Jonathan in various ways to break his spirit. But Dio's plan backfires when he forcefully kissed Erina Pendleton to shame her and deny Jonathan a relationship with her. When Jonathan learned of this, he pummels Dio before George intervened. Though Dio retaliated by placing Jonathan's dog Danny in the incinerator, he realized that he needed to change his plans a bit.
|“||JoJo... if it wasn't for you, I never would have received the power of the Stone Mask... But at the same time, it was your damnable meddling that cost me world domination! If there truly a god pulling the strings, then it is no coincidence our paths intersect.||”|
—Dio giving his personal realization to Jonathan
Seven years later, both boys attend Hugh Hudson Academy, where Dio intends to graduate as a top law student. During that seven-year span, he had acted brotherly and friendly toward Jonathan to lull the latter into a false sense of security. Now an adult, Dio decides to make his move and take the Joestar fortune by secretly poisoning George with the same poison he used to kill Dario. Jonathan realized Dio's plot after reading Dario's letter to his father, confirming Dio's intent and leaving his father with trusted physicians as he sets out to find an antidote and concrete proof of Dio's crimes.
Determined not to be stopped, Dio plans to subtly kill Jonathan by staging an accident with the Stone Mask. But upon learning that Jonathan entered Ogre Street, Dio mused he would not need to kill Jonathan himself. While wandering the streets of Liverpool, Dio encounters two drunkards and decides to test the mask anyways. By slitting the throat of one while using the mask on the other, Dio unwittingly transforms one of the drunkards into a Vampire who nearly kills him were it not for a timely sunrise obliterating his attacker. Returning to the Joestar estate, Dio finds Jonathan waiting for him along with Robert E. O. Speedwagon and an ensemble of constables who are to arrest him for attempted murder. Cornered and with nothing left to lose, having intended to kill Jonathan, deals a fatal stab wound to George and uses his blood to activate the Stone Mask. The constables shoot Dio repeatedly through a window, only for him to come back to life as a vampire and slaughter them.
Luring Dio away from Speedwagon, Jonathan battles the vampire while setting his home aflame in hopes that the fire will counter Dio's regeneration. After a short scuffle on the rooftop, Jonathan pushes Dio into the inferno and manages to impale him on a statue of the goddess of love; the combination of such a severe injury and the surrounding flames overpowers Dio, who seemingly burns away. However, a few days later when Wang Chan visits the charred remains of the house to find items to sell for profit, Dio resurfaces and drains his blood while vowing vengeance against Jonathan. After recruiting Jack the Ripper, Dio moves to the rural village of Windknight's Lot where he feeds on the populace to heal his body while building an army of zombies with the intent to take over London. Having sent Wang Chan to assassinate the supposed still recovering Jonathan, Dio is surprised when Wang Chan returns wounded and learns of the only thing besides sunlight that can destroy him: Ripple.
When Jonathan, his Ripple teacher William Anthonio Zeppeli, and Speedwagon reach Windknight's Lot, Dio hypnotizes a local boy named Poco who lures them to a graveyard filled with the undead. Dio reveals himself at this time, have mostly healed his body, and overwhelms Jonathan and Zeppeli by bypassing their Ripple attacks with his freezing ability. He then summons his strongest zombies, Bruford and Tarkus, to finish them off as he takes his leave. It is revealed later that Dio had also taken Poco's Sister, whom he attempts to bribe to join his undead legion. Unsuccessful, Dio leaves her at the mercy of Doobie, but Jonathan intervenes before anything grave happens. Finally, confronting Jonathan and the rest of the Joestar Group, Dio steps in to personally kill Jonathan. Nonetheless, Dire battles Dio first. The Ripple warrior is easily bested by Dio's ice techniques and his body is disintegrated, but Dire manages to injure Dio's eye before expiring. This drives Dio off the edge, summoning his zombies to kill the intruders while he proceeds to fight Jonathan.
In the battle that ensues on a balcony, Jonathan uses Luck & Pluck to sever Dio's right arm and nearly cleave him in half. Dio retaliates by freezing Jonathan's hands through the sword, and threatens to cut Jonathan's carotid. Fortunately, Jonathan had plunged the tip of his sword into a flame behind Dio, and the heat transmitted through the metal weakens the freezing effect. Jonathan breaks free, and Dio breaks Luck & Pluck. As Jonathan is reduced to fighting bare handed, Dio's freezing powers give him the advantage once again. However, Jonathan sets his own fists on fire and Dio, unable to freeze Jonathan's punches, cannot defend himself and is hit on the chest by a powerful Ripple-infused blow. The impact sends Dio flying down a cliff and the Ripple disintegrates his body. Yet Dio manages to sever his own head before the Ripple reaches it and survives the fall; a little later, his head is taken to safety by Wang Chan.
Two weeks later, Dio's head infiltrates the boat the newly married Jonathan and Erina use to travel to America and celebrate their honeymoon. Hidden in a booby-trapped coffin, Dio has Wang Chan cause a zombie epidemic on the ship to lure Jonathan to him. Once making himself known to Jonathan while admitting to had an epiphany that their fates are deeply intertwined, Dio reveals his intention to take Jonathan's body as his own. Dio then shoots beams of eye humor at Jonathan's throat in an attempt to instantly kill him, but the attack only fatally wounded Jonathan with his stopped breathing preventing him from using his Ripple. Regardless, Jonathan uses his remaining Ripple to sabotage the ship to explode in a final attempt to end Dio for good. After putting Erina inside the coffin to protect her from the engine's explosion, Jonathan holds Dio's head in his arms. Dio begs Jonathan to let him live while temping him with eternal life, but realizes too that Jonathan had expired. The sinking ship explodes, though Dio succeeds in taking Jonathan's body and sinks into the depths of the Atlantic Ocean.
In 1983, Dio's casket is recovered off the coast of Africa by fishermen, who are implied to have been killed by him shortly after. Dio then seems to travel a great deal, ranging from Egypt to Japan. Around July–August 1984, he impregnates a Japanese woman who goes on to give birth to Giorno Giovanna. The following year, he meets Enya the Hag and gains a Stand power (The World) as a result of the Bow and Arrow. Later that same year, he encounters Jean Pierre Polnareff and brainwashes him.
In 1988, he first meets Enrico Pucci while hiding in a church waiting for the sun to set. July of that year, he goes on to encounter Muhammad Avdol in Egypt and around the same time, his Stand experiences its first instance of stopping time. In August, he meets Noriaki Kakyoin while the latter is vacationing in Egypt and fights and brainwashes him as well.
|“||Don't you Joestars ever give up?!||”|
—DIO to Jotaro after showing The World's superiority
The awakened Dio Brando, now referred to as simply "DIO", begins his next moves within the later months of 1987. For much of this time, DIO remains in shadows, and the question of exactly what his stand "The World" does is a mystery to the Joestars and their companions. DIO's ambition is to create a perfect world for him and his servants. In the interim, he seeks to drain for himself the blood of the Joestar lineage, which will help him to fully fuse with Jonathan's body and take better control of The World.
Despite his knowledge that Joseph Joestar and allies are looking for him, he does not make any effort to go confront them himself and instead chooses to remain in his mansion reading or feeding on the blood of women. DIO spends a fair amount of time philosophizing in his mansion with Pucci while the protagonists battle their way toward him.When Hol Horse reports on the defeat of Alessi and Mariah, DIO questions him about his inability to fight, which makes the cowboy turn against DIO. DIO surprises him with his power, leaving a fearful Hol Horse to return to his side. Not long afterwards, when Vanilla Ice comes to inform him of Telence T. D'Arby's defeat, Vanilla volunteers his life to complete DIO's assimilation of Jonathan's body and subsequently slices off his own head. DIO then utilizes his own blood to revive Vanilla as a vampire. After Vanilla's defeat, DIO's face is reveals himself before the Joestar group for the first time when he confronts Polnareff on a set of stairs. He toys with Polnareff for a while but when it becomes clear that Polnareff won't rejoin his ranks, DIO prepares to kill him - only to be interrupted by Joseph, Jotaro and Kakyoin breaking down a wall and flooding the stairs with sunlight. then flees to higher ground. With the sun setting, the remaining Joestar companions split up into two groups and DIO follows Joseph and Kakyoin, who have commandeered a truck. DIO does much the same by taking over a limousine and forcing the senator inside, Wilson Phillips, to act as a chauffeur. During the car chase, DIO is attacked by Kakyoin's Hierophant Green but comes out unscathed thanks to The World, which he uses to counterattack. In order to get close enough to Joseph and Kakyoin's truck, DIO launches the senator at them, thus resulting in their truck crashing into a building. He then follows them as they use their stands to flee across the rooftops, and ends up battling Kakyoin in the process. Kakyoin is able to use his Stand to make a barrier from which DIO can't escape without getting hurt. DIO uses The World to stop time and destroy the barrier, punching Kakyoin through the stomach and back. Before dying, Kakyoin realizes the nature of The World's time-stop power and uses his last strength to give Joseph a message. DIO wastes no time in catching up to and attacking Joseph, who is able to pass Kakyoin's message to Jotaro before he is also killed by DIO's Stand. After a long and bloody battle between DIO and Jotaro, the latter is able to stop time just before DIO drops a steamroller on him, and wounds DIO's leg. Jotaro plans to keep on breaking DIO's leg whenever it regenerates until the sun comes up and kills him. DIO, determined not to lose, squirts some blood out of his leg and into Jotaro's eyes. He then attempts to escape but to no avail. In the end, Jotaro lands a punch which connects with a kick from DIO. The kick connects at approximately the same point on The World's leg as where DIO broke his. Because injuries to a Stand and its user echo each other, this is where The World's own structure was weakest. Jotaro's hand breaks but DIO's upper body starts to crumble, and his head shatters. Jotaro and doctors from the Speedwagon Foundation are able to do a blood transfusion between Joseph's body and the lower half of DIO's body. The transfusion is able to revive Joseph, and later they lay DIO's remains in the middle of the Sahara Desert to evaporate with the rising sun.
After DIO's death, it is revealed that he, along with Enya, had more affiliates beside those discovered by the Joestar group. The Nijimura Patriarch, like others, sold his soul to DIO and had a flesh bud implanted on his forehead, similar to Polnareff and Kakyoin. However, it burst after DIO's death, mutating him for life. Sometime before Enya died, she gave the Nijimura Patriarch one of the Arrows in their possession which one of his sons used to create Stand users in Morioh. Yoshihiro Kira was also revealed to have been given an Arrow before his death. Kira used this Arrow to create more Stand users in Morioh as well, including his own son Yoshikage.
Around twelve years after their battle in Egypt, Jotaro Kujo learns that DIO had at least one child, utilizing Jonathan's body, after his casket was pulled up from the ocean. It is later discovered by Koichi Hirose that this son was Giorno Giovanna. After DIO's defeat, Polnareff took the stand arrow from his mansion.This then lead Polnareff to go to Italy and track down Diavolo after finding out about the arrow in his possession.
In the year 2012, the Joestar family learns that Enrico Pucci encountered DIO shortly prior to and during their journey to Egypt. DIO "healed" Pucci's disfigured foot and gave him a Stand Arrow, speaking about the gravity which draws people together. He then told Pucci to seek him out using the Arrow if he wished to learn more. After a series of unfortunate events which led to Pucci being stabbed by the Arrow and gaining a Stand, he turned to DIO.
The two would spent a considerable amount of time together, each traversing to the other's location across the world and discussing ways to turn their philosophies into reality. During one of DIO's visits, he suddenly brings up his interest in reaching an ideal heaven, revealing that he had written the plans to do so in a notebook and that he would need Pucci's help in doing so. DIO questioned Pucci's loyalty to him, however, pondering why the latter didn't use Whitesnake to remove The World from him. Pucci explained that he loved DIO as he loved God, and thus worshiped him too much to betray him. Ensuring that he wouldn't completely fade, he left one of his bones in Pucci's care.
This bone becomes vital to Pucci's plan when one of his underlings, Sports Max, uses his Stand to reanimate it. This results in the incubation of a "Green Child" (which also possessed the Joestar birthmark) that would later merge with Pucci to give him C-Moon and finally Made in Heaven. Aside from Pucci, several other figures emerge, shown to have ties to DIO: Johngalli A is one of DIO's underlings who bears a grudge against the Joestars for DIO's demise, and Ungalo, Rikiel and Donatello Versus are, like Giorno, DIO's illegitimate children.