Ashley Benjamin Arnopp was convicted and sentenced for his part in the brutal slaying that lasted for more than an hour on the night of December 22, 2006.
Gilling, 18, maintained his not guilty plea when a fresh trial began in the High Court at Palmerston North yesterday.
The trial is set down for seven days.
In his opening address to the jury, Crown prosecutor Paul Murray said Arnopp would take the stand for the Crown.
"He is willing to give evidence but you'll hear, perhaps naturally or understandably, he sought reward for that," Mr Murray said.
"None has been given, nor will it be."
Gilling, Arnopp and Mr Waipouri had been drinking, smoking cannabis and taking party pills before the "sustained and ferocious" attack at Mr Waipouri's Rangitikei Street flat.
Mr Waipouri, 39, was found naked from the waist down, with injuries to his head and neck as well as various internal injuries.
The tip of his penis had been "removed", Mr Murray said.
"You have to consider the state of mind and the intent of the accused . . .the scene can tell you everything about what happened," Mr Murray said.
But Gilling, who was 17 at the time, said he was asleep at the kitchen table throughout the attack.
Gilling's counsel Mike Antunovic told the jury the evidence of medical pathologists would be an important part of the trial.
Which injuries caused Mr Waipouri's death and who inflicted those injuries was crucial to the defence case, Mr Antunovic said. "Some of the evidence you will see and hear will disturb you. . . will no doubt cause you to have some strong feelings against the accused.
"Feelings of that kind must be put to one side."
Gilvling sat face down as witnesses spoke of the hours leading up to Mr Waipouri's death.
Charlene Papara described the "bad vibe" she got while visiting her good friend, Mr Waipouri's neighbour, that day.
Arnopp and Gilling were sitting outside Mr Waipouri's flat about lunchtime, glancing up only briefly as she walked past, she said.
"They weren't doing anything unordinary but it's the feeling I got from them sitting there. . . I just felt uncomfortable.
"I'm not saying I shrugged it off but when I found out what happened the next day, to me it was like somebody up there was trying to tell me something."
But Mr Antunovic said her concern could not have been that great because before leaving she sent her 11-year-old daughter back past the men to collect a soft drink she left behind.
Her oldest daughter Ashlee Papara, who was visiting the same address later that night, spoke of loud hip hop music and a constant thumping coming from the flat above. "They were like as if someone was jumping up and down, but constantly."
Two attempts to quieten the men failed.
Her partner at the time, Trinity Hemo, was faced with a gruesome scene when he confronted the men after an empty beer bottle was thrown at him from the flat above, the jury was told.
Through the open door of Mr Waipouri's flat Mr Hemo could see a semi-naked body lying in the living area.