The proceeding begun with Moko's mother, Nicola Dally-Paki, uncle and grandmother reading their victim impact statements.
Ms Dally-Paki told the court of the anger and pain she felt that she couldn't see her boy through to his fourth birthday.
"On his fourth birthday I visited his grave, something I never planned to do. This year he would have turned 5 and I would have got him ready for school, but instead I had to bury him ... I have a horrible pain in my heart ... My boy - my children - are the centre of my universe and my world has changed forever."
She said that she did not know Haerewa well, but now knew he and Shailer were monsters who subjected her child to hell.
"The pain and upheaval in my children's and my life is never ending ... I would easily exchange the pain that Moko endured and have that inflicted on me if that would save his life. I would take the beatings, the horrific abuse, that they gave my son. I would take being kicked and bit, I would take all of the torture if that would save Moko's life.
"But I can't, Moko is lost to me forever. My son should have never died this way, no child should ever die this way. In my mind Tania and David's actions were premeditated. Tania even tried to blame Moko for his own injuries, who even does that? Tania even tried to blame me. Who the f*** does that? Tania and David did and that is why they are evil," she said.
"My sweet, innocent, vulnerable baby ... Tania and David do not deserve mercy, they had no mercy for my son."
Justice Sarah Katz thanked Ms Dally-Paki for her statement, saying the depth of pain she felt could only be imagined.
Moko's uncle and grandmother both spoke to the court about how Moko was a cute, happy, mischievous boy, whose death had sent a "shockwave of sadness" through the family.
"When I think about the hideous acts you continuously inflicted day after day, my heart aches and the sorrow is too much to bear," Moko's uncle said.
"You two have committed acts of the upmost evil that have shocked a nation ... tears have flowed and they have never stopped flowing since.
"We're the ones being punished, it's a life sentence for us. Moko's father will never be able to take his son fishing, his mother will never be able to get him ready for school -- you have taken away these small but precious moments."
Moko Rangitoheriri's mother Nicola Dally-Paki delivers a victim impact statement during the sentencing of Tania Shailer and David Haerewa. Photo / Ben Fraser
Crown Prosecutor Amanda Gordon had asked for the maximum penalty of life imprisonment for Shailer, saying the totality of the offending made it one of the worst cases of manslaughter imaginable.
"In the days prior to Moko's death the violence against him reached a level of torture with the defendants encouraging and supporting each other.
"No sentence will bring Moko back, no sentence will change what has happened."
Shailer's lawyer Ron Mansfield said while there was never justification for taking another life, especially that of a child, Moko's behavioural issues, accompanied with social economic stresses and mental health issues, placed Shailer under enormous stress and led to her acting "entirely out of character".
Mr Mansfield stated Shailer made "real and genuine cries for help" in the lead-up to Moko's death that she was not coping emotionally or financially. These factors led to a sharp decline in her health and resulted in her abhorrent behaviour.
He said Shailer was, once treated, at a low risk of reoffending and was extremely motivated to continue seeking help.
Haerewa's lawyer Harry Edward said his client was sorry and was under "no illusion of the inevitability of a custodial sentence".
Mr Edward spoke of Haerewa's early life which saw him lose both his parents at a young age - his father when he was 1, and his mother when he was a teenager - and the transient lifestyle he lived.
Moko Sayviah Rangitoheriri. Photo / Supplied
Haerewa began offending at about 13 years old and has since appeared regularly before the court.
A diagnosed schizophrenic, Haerewa had been fully medicated at the time of the offending and did not seek a sentence allowance for his condition.
"[Haerewa] was out of his depth and lacked the skills to cope with the increasing pressures brought on by the introduction of two other children into his care.
"He was ill-equipped to act as a caregiver to six children, four of them his own, without support ... He had no prior knowledge or notice of Moko and his sister coming into his and Shailer's care and this placed him in a circumstance he was unsuited for."
Justice Katz read the summary of facts to the court, detailing the ordeal Moko endured in the two months leading to his death.
She read how Moko was tortured by Shailer and Haerewa who kicked, stomped and slapped him. Haerewa rubbed his own faeces in his face. Moko was eventually beaten to the point where he suffered facial swelling, internal bleeding, septic shock from his leaking bowel and swelling of the brain.
March for Moko in Rotorua. Photo / Ben Fraser
The toddler was left for four days suffering those injuries before the couple rang 111, saying he had fallen off a wood pile.
He died "despite the best efforts of medical staff to resuscitate him", on August 10, last year.
During the reading, Ms Dally-Paki had to remove herself from the courtroom, succumbing to tears. Other members sat silently sobbing while consoling each other.
Both Shailer and Haerewa kept their heads dipped with Shailer raising her red-rimmed eyes periodically before lowering them again.
Haerewa admitted to police that he continually assaulted Moko, especially during the four days prior to his death.
The main injuries that caused the toddler's death were inflicted by Shailer, who forcefully stomped on his abdomen and stomach. The summary states it is unclear when she did this, but evidence suggests it was on August 6.
Justice Katz said that while the court accepted there was a range of reasons Tania Shailer and David Haerewa struggled to cope with their circumstances, including financial struggle and mental health issues, other families in similar situations "did not brutalise and kill the children in their care".
"You both assaulted Moko continuously and encouraged each other as the offending escalated. You embarked on a joint campaign of violence against a defenceless and extremely vulnerable child.
"The offending was extremely cruel and callous, with neither of you seeking medical help for Moko while he lay dying."
She said pre-sentence reports indicated Haerewa had very little remorse, if any, and Shailer had shown little insight into her offending.
"[Haerewa] tried to shift the blame onto Moko and his mother, as well as social services ... It has been concluded [Shailer] is either in denial of the gravity of her offending or does not have much insight into her offending."
When delivering the sentence, Justice Katz said to the pair that Moko "died at your hands in the most brutal way and your sentence must reflect that".
She said had it not been for the guilty pleas entered by the pair, affording them a discount on their sentence, they would have faced a sentence of life imprisonment.
Outside the courtroom, Moko's uncle thanked the people rallying around the country and marching for his nephew.
"At the end of the day, justice will prevail," were the words of the slain 3-year-old's father, Jordon Tawa Rangitoheriri, as he left the court from the back entrance.
