The 27-year-old, who cannot be named, appeared before Central local court via video link from Silverwater correctional complex and was expressionless as the pleas were entered.
Documents tendered in evidence indicate the boy, who died in May 2013, had previously been well cared for by his mother.
But when in January 2013 she struck up a relationship with a producer of Christian hip-hop music - who also cannot be named - things allegedly began to change.
The mother, the boy and his two siblings moved into the man's music studio in Sydney and she became quickly influenced by his "parenting philosophy", according to a statement of facts.
The boyfriend did not accept that the gentle, softly spoken and docile boy had a moderate intellectual disability, allegedly saying it was just a "behavioural thing" and he needed to "toughen up".
In the following months, the boy was subjected to prolonged and varied abuse.
Although toilet trained, he and his siblings wore nappies in the studio to defecate and had to urinate in buckets as it had no toilet facilities.
Then in a series of films, the boyfriend allegedly directed the children to hit their seven-year-old brother, yelling "soldiers, what is your profession?" - a reference to the Spartan movie 300.
In the same month the boy was spotted in Bulli, south of Sydney, being chased with a stick, forced to run along a beach in boot-camp style training and hit repeatedly with a spatula.
He seemed "skinny and undernourished" and his lips were cracked and swollen from dehydration, one witness reported.
The abuse was reported to police but officers said they saw no injuries when they visited.
In a video recorded by his mother a month before his death, the boy is seen being subjected to a form of discipline featured in the film Karate Kid.
She is heard saying: "[He] is on an eating plan. He gets bare minimum."
The boyfriend allegedly told a friend he had shaved off the seven-year-old's eyebrows and hair so he looked like the character Neo from the Matrix films.
By April, the mother believed her son was "an evil spirit" and told the boyfriend the devil had attacked her twice through the seven-year-old.
On 21 May, 2013, she called Triple-0 and said "my son was playing on a pogo stick ... he fell over and I think he banged his head".
When emergency services arrived, the boy was in rigor mortis.
An autopsy found he had died from swelling on the brain caused by a large haemorrhage, which is treatable if medical assistance is sought.
He also showed signs of older injuries, including broken ribs and fractures to his left foot and a finger.
The mother later admitted the pogo stick story was false.
She is to appear in the supreme court in May. The boyfriend, who has been charged with murder, is due to appear in court on Wednesday.
- AAP
