Nine schoolboys charged over “a vile, horrific” attack of a man in inner-Sydney last week allegedly “gloated” about the crime in a WhatsApp group chat, a court has heard.

Magistrate Jeffrey Hogg said the alleged stabbing in Pyrmont on Friday had left the 36-year-old victim with “injuries that are extraordinarily severe and life-changing”.

For the first time, a 15-year-old boy fronted the Children’s Court in Surry Hills from a cell at Cobham Youth Justice Centre at Werrington on Wednesday, but had his bail application rejected.

NSW Police Prosecutor Kai Jiang said the boy showed some remorse during a police interview, but argued against his release.

“It was active participation in a group chat post the alleged incident, where they have shown to be gloating about the injuries inflicted – almost proud of their involvement and infliction of violence,” he said.

“They took humour to the serious injuries inflicted, and it’s likely the complainant will be traumatised for life.

“The injuries inflicted are permanent and at the extreme level of seriousness, resulting in permanent disfigurement to the complainant’s face and a high likelihood of removal of his eye.”

The boy’s father, who was in court, fiddled with his hands and looked at the ground when a photograph of the man’s injuries was presented to Magistrate Hogg during the bail hearing.

The teen’s lawyer conceded it was “an extremely serious matter”, but argued any risk to the community could be mitigated by a house arrest arrangement and 24-hour parental supervision.

An argument was also made that the boy previously struggled with mental health issues, but Magistrate Hogg said he was yet to see evidence supporting that claim.

“I’ll accept that is the case, but I do place on record that there is no evidence to support that statement,” he said.

Magistrate Hogg agreed it was “an extremely strong prosecution case” and refused the 15-year-old bail, referring to evidence of “gloating about the offences” in a series of social media messages.

He described the alleged crime as “vile” and “horrific”.

“This young person was actively seeking to avoid arrest by police for a number of days, and is in a group conversation with the offenders, gloating about the offences, discussing plans to avoid arrest and taking revenge against any co-offenders who speak with the police,” he said.

“This is distinctly contradictive of remorse.”

If found guilty of the charges, the 15-year-old faces a maximum of 25 years behind bars.

The case returns to court later in 2020.

-ABC