Jailing 60-year-old John Michael McDermott for the rape of a schoolboy, Omagh Crown Court Judge David McFarland said the village of Donagh, near Lisnaskea, had witnessed "a tidal wave of abuse."
Two other brothers, 61-year-old James McDermott and 52-year-old Owen Roe McDermott were deemed unfit to plead, and were made the subject of a two-year Supervision and Treatment Order, although a jury found they had abused children as detailed in the 19 charges they had faced between them.
They like their brother John, who will serve three years probation on his release from prison, were also put on the Sex Offenders' Register for life.
The eldest of the brothers, 62-year-old Peter Paul McDermott took his own life the day after he went on trial in Enniskillen accused of indecently assaulting two boys.
Judge McFarland told the "deviant" brothers, who lived together in the village, that "in some respects Donagh is a quiet picturesque village in co Fermanagh, but it was a far from idyllic childhood for those growing up there."
The judge said youngsters "had their childhood stolen from them" and were "subjected to horrific abuse", and that it was "also clear that other adults were involved".
"It is also clear that there are allegations that other adults were involved in this systematice abuse".
Later Judge McFarland declared: "In short his was a village that had an appalling secret, and it was the children who bore the brunt of the tidal wave of abuse."
"Having considered all the evidence , my assessment is that within this community there was a substantial background of physical dominance and bullying by adults over the children.
"As a consequence, the younger children were not treated with any respect or dignity, they were physically abused, emotionally abused, and untimately sexually abused," added the judge.
Between them the brothers faced a total of 61charges against six victims, both boys and girls committed over five decades from 1969 to 2002, and involved the rape of one boy, the attempted rape of a girl, gross indecency, indecent assaults, and even a threat to kill to ensure silence.
Witnesses had told a court that the brothers would appear out of nowhere and were like a plague, a blot on the landscape preying on youngsters, sometimes plying them with alcohol.
One victim described how he felt like a prisoner in his own home, fearing that when he went out a McDermott brother would show up sooner, if not later.
"They would just appear at any place at any time.
"They were like Meerkats. If you were in a field they would just appear in it," he claimed.
Prosecuting lawyer Simon Reid described the sex abuse as "frequent, regular and persistent both in the village of Donagh and surroundng countryside"
The brothers he added would sometimes use "sly inducements to exploit the innocence" of children, while on other occasions they resulted to brute force, "to overpower them".
Defence lawyer Martin Rodgers said the only mitigating factor in the case was the guilty pleas of John McDermott, saving five of the victims having to "rehearse their pain" in open court.
"The facts of this case are horrendous and unique," said Mr Rodgers, who added that the brothers came from a highly dysfunctional family.
It was not clear, he said, how the abuse first began or how it spread from brother to brother.
The six victims of the McDermott brothers said later while they felt justice had been done in the case of John Michael, his two brothers had used a "loop-hole in the law " to escape justice.
However, the victims said while they understood Judge McFarland "acted within the restraints of the law, there should be a review of the Mental Health Legislation".
"There should be a half-way house where those suffering mental health issues could be kept under 24hour supervision, instead of them currently being allowed to use the loop-hole in the law and escaping justice," said a spokesman.
In a statement issued on their behalf they said: "For some of us it has taken 38 years to get this far.
"Each and every one of us has had to speak about a very painful part of our lives which we would all rather forget.
"We have had to open up and relive the abuse endured by all of us as children".
"The last couple of years," they said, "has been a long and painful journey for everybody involved in this very tragic case", but they hoped they have helped to break the "cycle of abuse which has preyed upon children for generations" which went unchallenged or detected.
Such children, often through guilt or shame, blamed themselves for what occured and that it has long been recognised that the effects of sex abuse were long lasting, and the mental impact can be devasting, according to the statement.
However, the victims said while abuse of any kind can rock a child's foundations: "It is our hope by the action taken by us we have saved others from having to endure similar pain in future".