Diavolo/History

History
Diavolo was born in an all-female prison sometime in 1967. His birth is a mystery because his mother claimed that he was conceived two years before her sentence and all the guards were female. Because she was unable to raise him while in prison, Diavolo's mother sent him to live in her home town of Sardinia with a priest.

When he turned 19, as the priest was constructing an apartment for him, Diavolo discovered his mother buried alive under a stone tablet. Around the same time, a fire broke out, Diavolo and the priest were among the seven who died. Diavolo, however, managed to survive and created Passione soon after. During that time, Diavolo found the six arrows in Egypt and quickly ran off with them. He then sold five of the Arrows to Enya Geil and kept the remaining one for himself (the same arrow attached to Polpo's Black Sabbath). He also had relations with Trish's mother before Part 5 begins, though even she did not know of his true identity.

Between the events of Stardust Crusaders and Vento Aureo, he sets out to kill all his blood relatives and those who discover his identity to ensure his name is erased from existence. Subsequently, he took up the pseudonym "Soliddo Nazo". Polnareff attempted and failed to assassinate him at one point before Vento Aureo. He was tossed off a cliff and sustained critical injuries, including the loss of one of his eyes and the use of his lower legs. Due to his survival, Polnareff was considered to be the biggest threat to Diavolo.

2001 (Vento Aureo)
He finds out about his daughter and then gives orders to Bruno Buccellati and co. to protect her, but this was all just so he could finally meet her and kill her himself so that he could erase all major evidence of his identity.

Diavolo is first seen as Doppio, and after saving a kid from getting hit by a car, he (as Doppio) encounters a fortune teller that tells him about his daughter, his double personality and other things. Doppio "transforms" into Diavolo and trounces the soothsayer before musing his search for Risotto Nero.

Polnareff encountered Doppio accompanying the dying Buccellati, however not knowing the boy was secretly Diavolo. Polnareff was taken by surprise and tried to get the arrow away from Diavolo. Polnareff was severely injured by King Crimson, but not before using the arrow on his own Stand. Once he is found out, he pursues Buccellati's gang in hopes to kill his own daughter. He is eventually defeated and killed by Giorno Giovanna in Rome after Giorno's Gold Experience evolves into Gold Experience Requiem and is trapped in an infinite death loop by its effects. Losing the confrontation, Diavolo finds himself in constant situations where he dies in several different scenarios but resurrects to die again (examples being him getting stabbed by a drug addict, getting hit by a car, among many other fatal situations) unaware of how or when he will die; thus, he's doomed to suffer for eternity. The last time he is seen, he screams at a young girl in terror and tells her to stay away from him, having become completely insane.

Synopsis (Doppio)
Although Doppio is an alternate personality, Diavolo takes on a completely different physic form when he changes into Doppio. Doppio, however, is unaware of this, and considers himself as Diavolo's most trusted subordinate. Doppio acts as a sort of disguise for Diavolo when he interacts socially with others in the outside world. While doing so, he only reverts into Diavolo when someone finds out about his true identity, or if someone angers him, this happens when Doppio claims his head hurts. Usually, after Diavolo takes care of the immediate problem, Doppio would resurface being oblivious to what transpired. Doppio communicates with Diavolo with any number of objects (such as a frog or a young girl's ice cream cone) that, when he sees them, prompt him to make the sound "rurururu~" (るるるる~), similar to a phone ringing and is able to talk to Diavolo via the "phone" he is holding. Diavolo trusts Doppio much more than any other operative in Passione, going as far as trusting Doppio with the power of King Crimson, albeit weaker.

He dies when Silver Chariot Requiem switches up the souls of the inhabitants of Rome. He ends up switched into Buccellati's body, and is subsequently shot and killed by Diavolo (who secretly took over Trish's spirit in Mista's body).