UPDATE: New details in the Monday death of MMA fighter Kimbo Slice make his passing at the age of 46 even that much harder to stomach.

The South Florida Sun Sentinel is reporting that Slice, real name Kevin Ferguson, was diagnosed with heart failure and was in need of a heart transplant right before his death.

In fact, at the time of his passing on Monday night, doctors were in the midst of trying to transfer him to a medical facility in Cleveland, so that he could be placed on an organ donor list immediately.

The Sentinel additionally adds that Slice had been experiencing severe abdominal pain combined with nausea and shortness of breath leading up to his untimely death.

"He went to Germany around March and got really sick while he was there," Mike Imber, Slice's manager and childhood friend, told ESPN about the time leading up to the MMA fighter's death. "I don't know what he thought it was, but he just felt sick. On Friday (June 3), he had bad chest pains and went to the hospital. I went and visited him on Friday and he seemed OK. I didn't feel like I was going to lose my friend in two days, by any means. He seemed concerned, but he seemed all right."

Imber added: "I talked to him that Saturday and Sunday, and he was still in the hospital. I said, 'Something's not right.' On Monday, his wife called and told me he had stopped breathing."

Too sad.

PREVIOUSLY: The mixed martial arts community is in shock.

Fan-favorite fighter Kimbo Slice died Monday, Bellator MMA confirmed to ESPN. He was just 42 and is survived by six children.

The former internet sensation bared-knuckled street fighter turned MMA pro is credited for bringing notoriety to the sport on a mainstream level via his backyard brawls and appearance on the UFC's The Ultimate Fighter reality TV series in 2009 and also for helping to popularize it within urban audiences.

Slice, real name Kevin Ferguson, was hospitalized in Margate, Florida, for undisclosed reasons earlier on Monday before the shocking news of his death was announced later in the day. Although no foul play is suspected, as of press time, the cause of his death is unknown.

Kimbo had just defeated Dada5000 (Dhafir Harris) via a three-round decision this past February, but the result was changed to a no-contest after Slice tested positive for anabolic steroids and higher than normal testosterone levels. 

"We are all shocked and saddened by the devastating and untimely loss of Kimbo Slice, a beloved member of the Bellator family," Bellator president Scott Coker said in a statement, as reported by ESPN. "Outside of the cage he was a friendly, gentle giant and a devoted family man. His loss leaves us all with extremely heavy hearts, and our thoughts and prayers are with the entire Ferguson family and all of Kimbo's friends, fans, and teammates."

With his signature long beard and imposing, wide-bodied 6-foot-2, 225-pound frame, the Miami representer —  who was homeless for a period of time —  first splashed onto the scene as an internet sensation years ago, bloodying anyone in his path in a series of backyard scraps.

Perhaps none of those fights were more infamous than the sight of Kimbo leaving this challenger in a pool of his own blood — making him a viral sensation before becoming a viral sensation was even a thing.

These unsanctioned fights made Slice a bona-fide internet star in the wheelhouse of YouTube's infancy, gaining enough notoriety to go pro as an MMA fighter. Although he was never truly skilled in MMA as far as the ground-and-pound technical elements of the sport, he swung and landed enough heavy punches to amass a 5-2 professional record with four TKOs, including his victory over MMA legend Ken Shamrock last year.

Upon learning the shocking news of his passing, Shamrock was among the MMA fighters who paid his respects to the street-fighting legend of Kimbo Slice. The fact that the likes of DJ Khaled, Shaquille O'Neal and Mike Tyson took the time out to weigh in on the loss show the impact Kimbo had on the fighting and the culture, overall.

Slice was scheduled to fight James Thompson on July 16 at the Bellator 158 event in London.

One of his children, Kevin Ferguson Jr., made his MMA pro debut this past March and will continue making his dad proud.

Rest in peace, Kimbo Slice.

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