Diavolo serves as the primary antagonist in the fifth part of the series. Born under unusual circumstances within an all-female prison during summer 1967, his mother claimed a two-year pregnancy with no identifiable father. Sent to Sardinia after birth, he was raised by a priest. Known as timid and not particularly bright during his youth, he aspired to become a sailor despite his adoptive father's wishes for priesthood. Around 1984-1985, using the alias "Solido Naso," he met Donatella Una during her Sardinian vacation. Their relationship produced a daughter, Trish Una, though Diavolo remained unaware of her existence. In 1986, at age 19, the priest discovered Diavolo's mother buried alive beneath their home, her mouth sewn shut. That same night, a fire consumed the village, killing the priest and several others. Presumed dead, Diavolo instead fled to Egypt. Joining an archaeological dig, he discovered six Stand arrows. He later sold five to the witch Enya Geil, who explained their power, and kept one for himself. This arrow likely granted him his Stand, King Crimson. Returning to Italy, he founded the criminal organization Passione, which grew dominant under his secretive leadership. Diavolo maintained absolute anonymity within Passione, issuing orders through intermediaries or digitally. He cultivated a benevolent public image for the organization through charity while secretly profiting from drug trafficking. This duality attracted idealistic members like Bruno Bucciarati. However, his brutality emerged when handling dissent; after the assassination team La Squadra Esecuzioni demanded better resources, he tortured and murdered members Sorbet and Gelato, delivering Sorbet's dismembered body as a warning. Around the 1990s, he crippled Jean Pierre Polnareff for investigating the arrows, leaving him for dead. His alter ego, Vinegar Doppio, functioned as a separate personality handling public interactions. Doppio believed himself the Boss's trusted subordinate, unaware he shared a body with Diavolo. Diavolo guided Doppio during crises, displaying occasional protectiveness, such as during Doppio's fight against Risotto Nero. In 2001, after Donatella's death, Trish's search for her father threatened Diavolo's secrecy. He ordered Team Bucciarati to deliver her under the pretense of protection, planning to kill her to eliminate any link to his identity. When Bucciarati discovered this during the Venice handoff, he rebelled. Diavolo mortally wounded Bucciarati using King Crimson's time-erasure ability and attempted to kill Trish, but Team Bucciarati escaped with her. Branding them traitors, Diavolo dispatched elite operatives like Cioccolata to eliminate them while personally pursuing leads to his past. Traveling to Sardinia as Doppio to prevent Leone Abbacchio from reconstructing his face via Moody Blues, Diavolo confronted and killed Risotto Nero. He then murdered Abbacchio in disguise. Later, during the Chariot Requiem incident at the Colosseum, body swaps fractured his soul: Doppio inhabited Bucciarati's body, while Diavolo occupied Guido Mista's body alongside Trish's soul. He covertly killed Narancia Ghirga before reclaiming his original body after Chariot Requiem's defeat. In the final confrontation, Diavolo seized the Stand arrow, but Giorno Giovanna impaled it first, evolving Gold Experience into Gold Experience Requiem. This nullified King Crimson's abilities and trapped Diavolo in an infinite death loop, forcing him to experience endless fatal scenarios across realities while remaining conscious of his perpetual suffering. Physically, Diavolo is tall and lean-muscled, with striking leopard-patterned pink hair, fragmented irises, and a mesh-shirt outfit. His personality revolves around an obsessive need for secrecy and control, stemming from a philosophy that destroying the past enables growth. This justified eliminating anyone threatening his anonymity, including family. He demonstrated pragmatism, avoiding unnecessary killings when possible, but exhibited extreme violence against perceived traitors. His confidence in King Crimson—which could erase up to 10 seconds of time and predict events via Epitaph—fueled a god complex, leading him to declare himself "emperor" or "king of kings." He viewed fate as favoring him, citing his supernatural birth and arrow discovery as proof of his destined supremacy.