SPOILER WARNING: Part 5 Spoiler details may follow.
L' Unità speciale (親衛隊,Shin'eitai, lit. "Guard Squad") is a secret elite subdivision in Passione.
They are deployed by Diavolo in an attempt to assassinate Team Bucciarati and Trish Una. Its members move after Bucciarati and his group betrayed their boss, although most of the members don't actually show loyalty to Diavolo. The group contains the minor antagonists of the second half of Vento Aureo.
There are five members of the guard squad. It is unknown if there were more, as Diavolo had no choice but to attack Team Bucciarati himself after Cioccolata and Secco are defeated.
★: The character is leader
(✩: Subsequent leader)
†: The character is deceased and passed on to the afterlife
☮: The character has resigned
⚓: The character retired (incapacitated) and/or their fate is unknown
👻: The character remains as a soul or ghost
The group is first put into action when Bruno Bucciarati and his gang defect from Passione. One by one, its members attack the traitors for different reasons.
The tag-team Squalo and Tiziano begin their attack when Diavolo planned for the traitors to be killed before leaving Venice, their incentive being money and the Boss' satisfaction in them. Using Narancia Ghirga as an initially hapless victim to Tiziano's Stand, they slowly and discreetly get the rest of the group more vulnerable and easier to kill with Squalo's Stand. Giorno Giovanna is targeted first due to his dangerous ability to, among other things, mend injuries. However, Narancia and Giorno, who is able to see past the deception of Tiziano's ability, work together and the two assassins are killed by Narancia out in public.
At the airport, Carne is sent to attack the whole gang, and is promptly killed by Guido Mista. His Stand, Notorious B.I.G, manifests on the gang's plane and incapacitates half of the group as they cannot escape, even forcing Giorno to lose both of his hands in his attempts to rid them of their invincible foe. However, Trish awakens her Stand, Spice Girl, with indirect encouragement from Giorno, and single-handedly defeats Notorious B.I.G by sending it into the ocean where it stays in the water indefinitely.
Later, the traitor group closes in on Rome, forcing Diavolo to deploy his last resort, Cioccolata and Secco. The two do not show true loyalty in Diavolo, and instead are fueled by Cioccolata's own morbid desires. When Narancia is unable to participate and Trish stays behind to tend to him, the rest of the gang is forced by the duo to split, with Mista and Giorno battling Cioccolata, and Bucciarati battling Secco. The confrontation leaves much of Rome's population dead or injured, with Giorno putting an end to Cioccolata in a helicopter, and Secco defeated by a dying Bucciarati right outside the Colosseum. With that, Diavolo decides to eliminate the traitors himself.