You thought this was a blog post, but it was I, DIO!

 

Dio Brando (japanese: ディオ・ブランドー, Hepburn: Dio Burandō), later also known only as DIO (ＤＩＯ（ディオ）), 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 (ディエゴ・ブランドー, Diego Burandō) bears resemblance to Dio and appears as a major antagonist.

The poor son of Dario Brando, an abusive alchoholic who worked Dio's mother to death, Dio first appears as a young misanthropewho, via the power of an ancient stone mask, becomes an immortal vampire A century after the events of the first part, he resurfaces as the user of the time-stopping Stand named The World. As the series' most prolific villain, his defining trait is his staunch ambition, which develops into a "might makes right" philosophy and a drive for absolute control through absolute power. 

 

Phantom Blood

In Phantom Blood, the child of an abusive drunkard named Dario Brando, Dio Brando becomes the adopted brother of Jonathan Joestar by using the promise that George Joestar made to Dario years ago. Upon entering the Joestar estate after his father died, Dio wasted no time unequivocally making young Jonathan's life a living hell to take everything from him including abusing and later killing Jonathan's dog, Danny. Dio underestimated Jonathan's retaliation for forcefully kissing his beloved Erina Pendleton, spending the next seven years feigning to be Jonathan's friend before enacting his plan to steal the Joestar fortune by poisoning George with the same poison he used to kill Dario. When Jonathan investigates the matter for proof, Dio plots to use an ancient  Aztecstone mask to murder Jonathan.

However, Dio learns the mask transforms the wearer into a vampire when exposed to blood, and uses it on himself when his scheme is exposed. Although seemingly killed when Jonathan impales him on a stone statue and leaves him in the burning Joestar mansion, Dio survives, and proceeds to start his subjugation of England in the small village of Windknight's Lot, amassing sired followers to his cause. Jonathan is sought out by Will A. Zeppeli, a master of an ancient martial art called Hamon, which can kill Vampires. He teaches Jonathan how to use this ability as Dio sends other vampires and zombies in his pursuit to kill him so he can take over the world.

Jonathan seemingly defeats him once more, but Dio's decapitated head survives. With the help of his servant, Wang Chan, Dio attacks Jonathan on a steam liner during his honeymoon with Erina in an attempt to claim his enemy's body for his own. Despite having his throat fatally punctured by Dio, Jonathan is able to use Hamon one last time to overload the ship's engines, with Dio apparently destroyed in the resulting explosion. Erina, escaping unharmed with an orphaned girl, survives with their unborn son. 

 

Battle Tendency

As he is dormant in the sunken ship, Dio Brando does not appear in Battle Tendency but the aftermath of his apparent death at the hands of Jonathan Joestar affects the plot. It is ultimately revealed that Jonathan and Erina's son George Joestar II, a famed pilot of the Royale Air Force in World War I, was murdered by one of Dio's zombie henchmen who survived the battle at Windknight's Lot and had infiltrated the RAF. George II's wife, the orphaned girl Elizabeth, hunted down this zombie and killed him with her Hamon. However, as no-one else recognized the zombie's true identity, she became a wanted murderer and was forced into hiding as Lisa Lisa with the help of the Speedwagon Foundation that was founded by Robert E.O. Speedwagon. Lisa Lisa would later encounter her son Joseph Joestar teaching him Hamon so he can defeat the Pillar Man, Kars, whose creation of the Stone masks made him indirectly responsible for Dio's transformation. 

 

Stardust Crusaders

It is revealed in Stardust Crusaders that Dio survived the ship's explosion by decapitating Jonathan's corpse and attaching his own head to it as the ship sank, he confined himself inside a casket at the bottom of the ocean for a century until a shipwreck salvage operation unintentionally retrieved him in 1983. Now known mononymously as "DIO", he soon meets the mystic Enya Geil who awakens both of his Stands, The World (世界（ザ・ワールド）, Za Wārudo), allowing him to stop the passage of time around him, and a Hermit Purple-like stand (technically Jonathan's Stand; one person could only have one Stand. Since Dio is using Jonathan's body, he could awaken and use Jonathan's Stand). As his head is attached to Jonathan's body, Dio's acquisition of The World also awakens Stand abilities in all of Jonathan's living descendants. While Joesph Joestar and his grandson Jotaro Kujo have the resolve to control their Stands, Joseph's daughter and Jotaro's mother Holly has her very life sapped away by her own Stand because of her gentle disposition. This spurs Jotaro and Joseph to track down Dio along with their friends Mohammed Avdol, Noriaki Kakyoin, Jean-Pierre Polnareff, and Iggy the Boston Terrier to kill him once and for all, freeing Holly from the curse the Stand has trapped her under.

Dio responds by sending other Stand users to assassinate the Joestars before they can find him in his mansion lair in Cairo, some of whom (namely Kakyoin and Polnareff) he had previously mind controlled and joined the Joestars on their journey after being saved by them. Along the way, Avdol and Iggy are killed by Dio's right-hand man Vanilla Ice, who in turn is killed by Polnareff. Dio kills Jotaro's friend Kakyoin in combat and then kills Joseph in front of Jotaro. During his battle with Jotaro, Dio is severely hurt and resorts to draining Joseph of his blood, not only healing himself but also finally completing his unification with Jonathan's body. Dio greatly strengthens his vampiric abilities and his Stand, but Jotaro's Stand, Star Platinum, proves to be The World's equally powered counterpart. After much effort, fuelled by the rage of his friends and grandfather’s deaths as well as his mother's dwindling health, by taking advantage of Dio's pride and desire to test his strengthened abilities, Jotaro finally manages to awaken his own time-stopping powers and overpower Dio with Star Platinum, successfully killing him.

Jotaro and the Speedwagon Foundation doctors revives Joseph via blood transfusion from Dio/Jonathan's corpse. Then Joseph and Jotaro take their ancestor's corpse out into the desert and expose it to sunlight, which disintegrates due to the vampiric infection, vanquishing Dio once and for all and allowing Jonathan to finally rest in peace after many years. 

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