TORONTO -- A biker convicted in what's believed to be Ontario's largest mass slaying feared he might "end up in the pile of dead bodies" himself if he didn't follow orders from his gun-toting gang brothers as they carried out the execution-style killings eight years ago, his lawyer argued Monday.

While in hindsight, Marcelo Aravena recognized he could have called 911 after the night took a deadly turn, concern for his own safety kept him from acting at the time, Delmar Doucette told the Ontario Court of Appeal.

He suspected the others -- three of whom had been meeting in secret throughout the night -- might turn on him and even begged them not to shoot him in the face if they decided to kill him off, Doucette told the three-judge panel in the first day of the appeal.

"In the moment... it is not at all clear who will be on what I call the team of the dead and who's going to be on the team of the living," he said.

Given the implied threat he faced, Aravena should have been allowed to use the duress defence at trial, his lawyer argued.

Aravena, a former mixed martial arts fighter with a history of drug addiction, is one of five men challenging dozens of murder convictions in a ruthless internal cleansing of the Bandidos motorcycle club that left eight members of its Toronto chapter dead.

In all, Aravena and five other men were convicted of 44 counts of first-degree murder and four counts of manslaughter in the April 2006 slaying. The bikers' bodies were found stuffed into cars and abandoned at a rural property near London.

All six men -- including the purported mastermind, Wayne Kellestine, on whose farm the murders took place -- filed notices of appeal shortly after their convictions in 2009, but appeal court documents show only five are now proceeding.

Court documents show Kellestine objected to being branded a "psychopath" at trial and took issue with other character evidence he deemed "massively prejudicial," such as Nazi symbols found on his farm.

The other four -- Aravena, Brett Gardiner, Frank Mather and Dwight Mushey --were portrayed at trial as power-hungry schemers or wannabes gunning for status in the outlaw motorcycle club.

Like Aravena, several are arguing on appeal that they should have been allowed to use the defence of duress.

The Crown argued at the trial that the murders were the result of rising tensions between the dead men and the probationary Bandidos chapter in Winnipeg. The prosecution relied largely on the testimony of a man who is now an informant but was a member of the Winnipeg Bandidos.

Kellestine, a member of the Toronto chapter and the one responsible for internal discipline, began to distance himself from the group and align with the Winnipeg men.

Court heard he received orders from the gang's U.S. headquarters to strip the Toronto chapter of their gang affiliation, effectively making himself the new national leader. The Winnipeg group were to help carry out the so-called patch-pulling.

Sometime in the hours before the killing, the plan changed to mass murder, court heard.

The informant testified at trial that Kellestine summoned the Toronto Bandidos to his farm for a meeting, then he and the Winnipeg group spent hours cleaning and loading weapons in preparation. At one point, the informant told the court, Kellestine said: "If we kill one, we kill them all."

The Crown argued that comment formed a conditional plan to kill and therefore constituted first-degree murder.

Most of the men who are appealing argue that was an error by the judge, to allow the jury to convict them on what is known as "constructive" first-degree murder.

Gardiner's lawyer said Monday that Kellestine's statement "does not constitute a plan at all," particularly since none of the others indicated they were on board.

The conviction of constructive first-degree murder wasn't applied to Gardiner, who court heard stayed in the farmhouse most of the night while the killings took place in the barn. However, the verdicts suggest the jury found he aided and abetted in six of the murders.

His lawyer Christopher Hicks said his client didn't know anyone would die that night, nor did he help the others commit the murders.

Gardiner, who court heard never held a gun or watched over the targeted men the night of the slaughter, should have been found guilty of manslaughter in all eight deaths instead of two, Hicks argued.

Even after it became clear that two men had been killed, there was no evidence at trial suggesting Gardiner's actions in any way helped in killing the others, though he did at one point remove items from the trunk of a car in which one of the bodies was later found, the lawyer said.

Aravena also argues he should have been convicted of eight counts of manslaughter.

Mather maintains he didn't kill anyone and that he was not a member or even official associate of the Bandidos, just a friend of Kellestine.

The only man convicted in the eight killings who appears to not be pursuing his appeal is Michael Sandham, who used to be a police officer in Manitoba, and who shot the first of the eight men.

The men killed that night were George Jessome, 52, George Kriarakis, 28, John Muscedere, 48, Luis Raposo, 41, Frank Salerno, 43, Paul Sinopoli, 30, Jamie Flanz, 37, and Michael Trotta, 31.

The court is scheduled to hear the challenge all week.