"This is a profound family tragedy. It's an unthinkable family tragedy," Justice Chrissa Loukas-Karlsson said on Friday afternoon.
The ACT Supreme Court judge made the remark, among several sobering comments, while sentencing a man for a range of child sexual abuse and incest crimes.
The now-25-year-old man is not named because he was a child during some of his offending and to protect the identity of his three victims - two siblings and a cousin.
"There are people in this courtroom and people who have given victim impact statements that are utterly destroyed by what you did to this family, do you understand that?" the judge said.
"Your victims are devastated."
Before handing down a six-year-and-six-month jail sentence, Justice Loukas-Karlsson warned those in the closed courtroom her nearly 100-page sentencing remarks made for "inevitably disturbing reading".
The offender, who has been behind bars for more than two years, will be eligible for parole in October next year after committing offences between 2014 and 2022.
He previously admitted to more than a dozen charges, including two counts of incest with a child, one of sexual intercourse with a child and an attempt to do so, and multiple counts of committing an act of indecency.
The man also pleaded guilty to using a child to produce exploitation material, supplying cannabis to a child, and two counts of making pornographic material available to a child.
The family house where many of those crimes took place, Justice Loukas-Karlsson said, "was not a safe home".
While the judge opted not to read out agreed facts from the case in open court, she cited from several previously heard victim impact statements.
"My life is not the same as it once was and I'm not sure it will ever be the same again," one victim had told the court.
"The toll cannot be measured."
That victim described being violated by her brother, whom she had trusted.
Another victim told the court he felt powerless in his own body and mind, and that panic attacks "make me feel as though I'm going to die".
"I go to bed every night afraid to go to sleep because I think I'm going to die in my sleep," he wrote.
That victim's mother said her son had become a "sad, anxious, scared and self-loathing man through no fault of his own".
"I had no idea how to stop it and I was scared it might also happen to others in my family," the third victim wrote in her impact statement.
Justice Loukas-Karlsson said the 25-year-old offender's prospects of rehabilitation were somewhat guarded but real given steps he had already taken.
The man told a pre-sentence report author he grew up up in a dysfunctional household and reported being sexually abused by a babysitter.
One of his siblings reported the man was subjected to ridicule and humiliation by the family.
"What happened to you as a small child is not your fault. But what you do is your responsibility," Justice Loukas-Karlsson said.
The man can apply for conditional release from custody, after which time he will be subject to "intense supervision", in just over a year.
"You'll only get parole if you continue to rehabilitate yourself," the judge said.
- Support is available for those who may be distressed. Phone Lifeline 13 11 14; Kids Helpline 1800 551 800; 1800-RESPECT 1800 737 732; Bravehearts 1800 272 831; Blue Knot Foundation 1300 657 380.
