Cassius Turvey, a Noongar Yamatji boy, died in hospital 10 days after he was deliberately struck to the head in Perth's eastern suburbs on October 13, 2022.
Jack Steven James Brearley, 24, and Brodie Lee Palmer, 30, were convicted in May of murdering the 15-year-old after a mammoth 12-week trial.
Mitchell Colin Forth, 27, who was also on trial in the West Australian Supreme Court for Cassius' murder, was found guilty of manslaughter.
The victim's mother, Mechelle Turvey, told a two-day sentencing hearing her son was a gentle giant who was unjustly taken from his family and his death "left a void that will never be filled".
Ms Turvey said Cassius's killers had "glorified" their crimes and thrust the innocent children who were with him into a "world of pain and fear".Â
"The physical and emotional scars they bear are a testament to the cruelty they have endured," she told the court on Thursday.
The impact of the killers' "heinous acts" also extended beyond their immediate victims, she said.
"Families are left devastated, grappling with the unimaginable pain of seeing their loved ones suffer," she said.
The community "now lives under a shadow of fear and uncertainty" after Cassius and the other children were racially vilified, confronted, chased and attacked, Ms Turvey added.
"That's the truth. If anyone thinks their actions were not racially motivated, many Australians would be left scratching their head," she said in a victim impact statement.
"The actions of the accused have torn at the very fabric of our society, leaving wounds that will take years, decades, if not lifetimes, to heal and recover.
"This indiscriminate targeting has left fear for the safety of all children."
Ms Turvey said Cassius was well-respected by his peers and a leader who was about to start his first job at Kmart, and no words could fully capture the devastation of losing someone you loved to violence.
"Cassius was not just part of my life," she said.
"He was my future, my family, my home. The day he was taken from us is the day my world shattered."
The trial heard Brearley delivered the fatal blows while "hunting for kids" because somebody had smashed his car windows.
It was alleged Forth and Palmer aided him in the common purpose, along with Aleesha Louise Gilmore, 23, who was acquitted of a murder charge.
The attack on Cassius followed a complex series of events that started on October 9 when Forth, Brearley, Gilmore and another man who was tried on lesser charges, Ethan Robert MacKenzie, 21, allegedly "snatched two kids off the street" before punching, kicking and stabbing one of them.
Four days later, Brearley and his co-accused allegedly armed themselves with metal poles pulled from shopping trolleys before climbing into Palmer's ute and driving off to search for some youths.
About the same time, Cassius and a group of about 20 fellow students caught a bus to the same area to watch a fight being talked about on social media.
Brearley, Forth and Palmer intercepted them near the field, and Cassius and some other "terrified school kids" fled into nearby bushland.
It was there that Brearley caught up with him, the trial heard, before the teen was knocked to the ground and hit in the head with a metal pole.
Cassius was struck at least twice, the impact splitting his ear in half and causing bleeding in his brain.
All told, the five defendants variously faced 21 charges over the events of October 9 and 13.
The jury found them guilty of all except Gilmore's murder charge and a theft charge faced by Brearley.
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