Diddy's Alleged Ugly Side Goes Back Decades, New Claims of Abuse in Report

Diddy has apparently been a Dr. Jekyll and Mr. Hyde character over the years -- either a super nice guy, or allegedly violent and vicious ... this according to a new bombshell report.

Rolling Stone just published a sprawling article about the embattled rap mogul -- detailing his life story and rise to fame starting in the '90s ... now coinciding with his current federal criminal investigation, which could land Diddy behind bars for a long time.

During their 6-month investigation, RS reporters reached out to 300-plus people in Diddy's world and interviewed over 50 former friends, acquaintances, employees, artists and industry insiders. Many of them refused to talk ... but those who did had quite a bit to say.

Several sources -- including close associates of Diddy's from his Bad Boy days -- claimed to RS he has a dark side and could be a menacing figure ... desperately seeking acceptance/ admiration while demanding public displays of devotion from others and splashy donations.

The Rolling Stone piece details several instances of either alleged outright violence -- or fits of rage ... which the outlet reports goes all the way back to his days as a Howard U student.

One alleged anecdote details a time in which Diddy gets accused of pummeling a record label executive who started dating his ex -- the late Kim Porter, whom he's alleged of abusing in this piece. He's also accused of not ever letting her really move on throughout what's described as a tumultuous and toxic relationship.

Other women Diddy has dated are also mentioned in this story -- including Jennifer Lopez, who RS reports was subjected to Bad Boy staffers trying to convey a message to her via Diddy after they split in an attempt to win her back. Apparently, Diddy sent these BB workers to 'TRL' studios to stand outside with signs ... begging her to get back with Puffy at the time.

Not only that, but, according to RS, Diddy made sexual advances to his female employees and other female associates/acquaintances throughout his reign ... one woman claims he'd approached her boss to solicit her for sex.

In yet another alleged instance, he's accused of attacking a woman at Bad Boy's offices -- which required employees to bust in and tear him away from the woman.

There's a lot more in this piece -- including claims that Diddy was jealous of Tupac's relationship with Biggie Smalls ... and that he wanted the spotlight after Biggie's death. Several Bad Boy associates/employees/ are described as hating the dude behind his back.

Despite all these ugly episodes that are described in the article -- there are positive sides of Diddy that are also touched on. Bottom line ... Diddy allegedly runs really hot or really cold.

Of course ... the backdrop here is the fact that a grand jury has now been convened, and witnesses are being contacted to potentially testify ahead a possible indictment. Despite his mounting legal challenges, Diddy has denied most of the wrongdoing alleged against him.