Justice Lang allowed the 14-year-old's name suppression to be lifted at his sentencing on Friday.
In a preliminary decision, he said he was inclined to allow the younger boy to keep his name suppression because he was found not guilty of the crime.
Straight after the verdicts were delivered in June, Mr Kumar's family spoke of their disgust at the outcome.
"The heart and soul of our family was taken away," the victim's son Shivneel Kumar said.
"We endured countless reruns of my dad's last moments. We tolerated all this to obtain justice for my dad."
Shivneel, supported by his sobbing mother Anita, said they now felt that had been for nothing. "We are now living in a society where kids are on drugs, roaming the streets with weapons at the ready," he said in June.
There was no dispute that the 14-year-old stabbed Mr Kumar in the neck, inflicting the fatal wound, or that the 13-year-old was standing outside with a metal pole.
But at their trial, defence lawyers for the boys detailed the boys' backgrounds and the psychologically debilitating effects they had on them.
Judge: Suppression will be lifted
In his brief verbal decision today, Justice Lang said: "At sentencing, name suppression for [the teen] will be lifted.
"But I'm going to direct that no photographic image is to be published and for that reason there will be no photographs of him at sentencing or filming by the television."
In relation to the younger boy, he said his preliminary view was that "the fact he was acquitted is a significant issue, coupled with his young age ... He should be subject to an order for permanent name suppression".
However, lawyer for the 14-year-old Maria Pecotic said she would be appealing the decision.
If she files an appeal before his sentencing date, media will not be allowed to name him until the appeal is heard.
Media organisations opposed the 14-year-old's suppression.
A lawyer representing NZME and other outlets said grounds for keeping the boy's name secret had not been made out by the 14-year-old.
And even if they had, "that ground is insufficient to justify and exercise of judicial discretion over-riding the presumption in favour of open justice", Bell Gully lawyer Tania Goatley said.
Ms Goatley told the court the risks the teen faced would be no different to anybody else leaving prison with a manslaughter conviction.
The 14-year-old did not have "an unusual or special case", she said.
"He has been convicted of a serious crime."
In written submissions, Ms Goatley said: "The overwhelming balance of the decisions to date concerning young offenders is that name suppression lapses once fair-trial considerations are extinguished."
"It is respectfully submitted that the media are the eyes and ears of the public and the public has the right to be informed as to the identity of the perpetrators of serious crimes," Ms Goatley said.
Publishing the 14-year-old's name could bring shame and difficulty getting a job later, but those were consequences of serious offending.
"It is the fact of his conviction which may pose future difficulties, not publication of his name. There is nothing unusual about this particular young offender to justify name suppression."
There was nothing about 14-year-old's situation that would class him as different to other young offenders convicted of serious crimes.
The High Court trial heard the boys' original idea was to break into a nearby shoe shop.
They changed their mind at the last minute and decided to target the dairy, meaning they had less than three minutes to plan the theft.
The Crown argued the armed robbery might not have been well planned but each of the boys wanted money and had weapons to achieve their goal.
When the 14-year-old was convicted of manslaughter he was remanded in Child, Youth and Family care.
He is one of about 10 children. A source close to the family had told the New Zealand Herald most of the children had been in and out of CYF care.
"We do not want to support injustice"
Arun Kumar's family will not attend the sentencing, saying there is no point as "justice will never be done"
Mr Kumar's daughter Sheenal today said the family would not be present in court.
"We see no point in attending the sentencing because we know that justice will never be done.
"Despite full CCTV footage, the use of weapons and witness testimony, our justice system came up with manslaughter for one and the other walked free. We do not want to support injustice and therefore there is no point in attending."
Ms Kumar said during the trial the jury heard much about the background of the accused youths and their families.
"However their criminal backgrounds and other recent criminal acts leading up to June 10 was hidden from the jury because the New Zealand justice system does not allow such offending to be taken into account. The concept of a 'fair trial' is indeed fair for the criminal but what about the victims?"
In a statement released today the family slammed the boys' defence lawyers and criticised the court system.
"We had a good chance to set a precedent for other youth walking our streets with weapons and committing similar crimes. Unfortunately this did not happen," said Ms Kumar.
"The last thing we wanted was for Dad's death to be in vain. Unfortunately this has happened."
Her family lived as "good citizens" and contributed positively to society - but that had earned them "nothing but grief".
"We wanted justice to take place though our court system and initially we were confident and had faith in our system but now this has been shattered," she said.
The family now felt "like idiots" and said Mr Kumar had been "insignificant" in court compared to the accused, who they believed were treated as "victims".
Ms Kumar said while his family were upset at the outcome of the trial, and the process which led to it, they were extremely grateful for the support they had received from the public.
- With additional reporting from NZME News Service
