05/01/2016 12:51 PM AEDT | Updated 15/07/2016 12:51 PM AEST

Cole Miller Death: 21-Yr-Old Fronts Brisbane Court, Charge Upgraded

Fairfax/ Cameron Atfield

One of the two men charged over the alleged one-punch attack that led to the death of 18-year-old Cole Miller will remain behind bars after facing an upgraded charge in court on Tuesday.

Fairfax Media reports that Armstrong Renata, 21, faced Brisbane Magistrates Court this morning on an elevated charge of unlawful striking causing death.

Renata was previously charged with grievous bodily harm.

According to a firm of Queensland lawyers, the offence of unlawful striking causing death is separate to murder or manslaughter and prevents a person from relying on the accident defence.

Renata's charge has been upgraded following the death of the promising water polo player in hospital on Monday.

It is the second time Renata has faced court over the incident in two days.

Outside court, the accused's lawyer Neil Lawler described the circumstances as a " tragedy for all concerned".

"He has never been in custody before. The watch-house is a pretty tough place," he told reporters.

"We have been basically talking about how the court process will work.

"We will obtain some police material and then perhaps make a bail application at a later date."

He said the charge carried the possibility of life in prison "with a minimum of 80 percent to be served or 15 years, whichever is the lesser".

He did not apply for bail and the matter was adjourned for mention on February 8, Sky News reports.

Renata's co-accused in the incident, 21-year-old Daniel Maxwell, is reportedly also due to face court on Tuesday.

An elite water polo player, Miller was allegedly randomly assaulted while walking with a friend in Brisbane's Fortitude Valley on Sunday morning.

His father Steven confirmed he died in hospital on Monday in an emotional press conference thanking hospital staff, police and the water polo community.

"He struggled bravely in the intensive care unit of the Royal Brisbane Hospital and our family and many close friends have been at his bedside since the incident,” Miller said.

“Cole was a beautiful, brave young man with his whole life yet to be lived.”

On Sunday, Detective Senior Sergeant Tom Armitt told reporters the victim and a friend were walking in the area when they were approached by four men.

"A short exchange has occurred and the victim was struck once to the back of the head, has fallen forward," he said.

"This is a random act of violence. There is no indication the victim knew who the offenders were."