Greg was born to George and Te Tangiamio Koroheke in 1950.
He was the youngest of their 14 children. All four boys joined the Mob and Greg's twin brother, Richard Koroheke, was the captain of the King Country Mongrel Mob until his death in 2014.
It was the way of life for boys from Hangatiki, a small rural town in the Otorohanga District. If you didn't have work or have an education, you joined the Mob.
"My life was rugged. My mum died when I was five and we slept on dirt floors … I never had the touch of a mother, I never felt that," Greg says.
"Just about everybody in our age group did farm work. We shore sheep, we worked in shearing sheds and haymaking.
“We were all in the Mob down at King Country.”
"It was only when I moved up here to Hamilton that I joined our local chapter. All I ever knew was gang members, Mob members. We would drink all day, there was a lot of violence …"
Greg moved to Hamilton in 1965. He spent, collectively, four years in prison for drink-driving and burglary. After his last stint in jail in the 1970s, he joined the army and worked as a gunner. In 1980, he worked for a Waikato bitumen company before the work ran out and he was laid off.
"Then we just came and sat at the pad every day, every minute, every hour … drinking, drugs.
"That was my life."
Greg has RAT tattooed on his right hand. He was practising his tattooing while he was in prison. He has Mongrel Mob Waikato and a bulldog tattooed on his right upper arm. But, unlike many other members, his skin is otherwise clean of gang ink.
Greg prepares toast and a cup of tea for his wife, Jocelyn.
His mokomoko [great-grandchild] runs in to give him a kiss before he leaves for the morning.
Greg asks Jocelyn where his reading glasses are. He spends 15 minutes looking for them - they're on the windowsill, but he walks past them twice before he realises. Jocelyn gathers the himene book and Bible.
Greg and Jocelyn drive the 10 minutes from their home in Grandview to the weatherboard building in Frankton. Greg gets changed into his flash clothes. He walks up the freshly concreted path to the front of the building and stops at the door.
He's early. He turns to greet members of his church who have turned up in busloads.
Right on schedule, he says.
"At the church, it is different. I can revert back to the Mob life any time I want to. After I've finished at the church and I've done a few services, buried a few, done cremations, you want to go back. Just for peace. But I haven't finished yet," Greg says.
"My identity would be as a reverend. I'm for the people, for the people."