Paul Greaney QC, prosecuting, said: 'In effect, over a period of time, Jimmy Prout was not just mistreated, he was tortured.
'In the end, this conduct was to cause the death of Jimmy Prout.'
He added: 'Awfully, on one occasion, Jimmy Prout's scrotum was sliced open and his testicle was removed; he was then forced to eat it.'
Mr Greaney said Mr Prout died on February 9 2016 and his body was dumped on wasteland where it began to decompose and was partly eaten by animals.
The group then allegedly set about covering their tracks as well as fleecing his bank account, asking people if they had seen Mr Prout as they pretended to look for him.
Zaman, who uses a wheelchair and was the leader of the group, was described as vengeful and controlling and was determined to get his own back after he thought Mr Prout had been involved in a theft against him.
The jury were shown CCTV images, often taken from cameras Zaman had on his house, of the worsening condition of Mr Prout as the assaults continued.
Footage from October 18 2015 shows him walking and jogging. But the next clip, from February 5 2016, showed him staggering along, being pushed by Corbett, before slumping on a fence.
Lastly the jury saw footage from 9.47pm on February 6 2016 in which all four defendants are seen with Mr Prout. He was in a 'dreadful condition', supported by Corbett and Rayworth, as they walked him to number 75.
That was the last time he was seen on any footage and it is alleged he remained there until his death on February 9.
Mr Prout was also posting pictures of his injuries on his own Facebook account at the time, with words such as 'My bodie hurt' and 'My sholder hurts'.
Following the seven-week trial, Mr Justice Dove said sentencing would take place on June 27.
Detective Chief Inspector Andy Fairlamb, from Northumbria Police, said it was hard to imagine that such vile assaults could take place in 2016.
'Jimmy Prout died on February 9, we believe, and was then taken to a copse and dumped by these four individuals who have all pleaded guilty to perverting the course of justice,' he said.
'Prior to his death, he was subjected to a number of serious assaults of a vile, degrading nature, which resulted in his health, both physical and emotional, deteriorating in the last weeks of his life, and to his death.
'The QC presenting the prosecution described the circumstances under which Jimmy died as from the Dark Ages, which you cannot imagine in 2016.
'Jimmy had some of his teeth removed with a chisel and a hammer, he had a testicle removed by having his scrotum opened up with a Stanley knife blade, severed, and then he was made to eat it.
'He was hit over the head with a Jack Daniel's bottle.'
He said Zahid Zaman co-ordinated what the group did and had exerted a 'controlling influence' over the three women who made up the gang.
'Before the end of 2015 Jimmy would have be a normal guy going about his normal day-to-day business but the evidence from CCTV, mostly captured from Zaman's house, is that Jimmy's health deteriorated greatly,' said Mr Fairlamb.
'You can see the change in him.'