He said he joined the gang originally because he was seeking "a sense of brotherhood and a sense of belonging to something".
He said he left after falling into a negative head space and realising he did not want his son to following in his footsteps.
Hiroki initially joined the Bandidos gang when he'd just moved to Christchurch, where he didn't know many people.
"I wanted to join it since I was a young fella, because they were always guys I had looked up to, but plain and simple, I didn't really know what I was getting myself into really. I thought I did, he said.
He added that he "lost himself along the way", just following what others were doing.
He climbed up the ranks and eventually became the president of the NZ chapter of the gang.
He said his first moment of clarity was when he visited his grandmother and she "noticed a change".
"She noticed that I certainly got a lot harder on the exterior and I couldn't see that because you can't see the changes when you're with yourself every day," he said in one of the videos.
The man also says he attempted suicide while he was part of the gang but his mental health has improved since he left.
He now runs a weekly support group in Christchurch for men facing similar challenges.
He tells teenagers in his videos to avoid gangs as they will not find the brotherhood he too had sought in them.
"I've had guys turn on me that were my best mates ... it's not a brotherhood," he said.
"It's a false sense of belonging to something, then at the drop of a hat everyone can turn on you."
He also warns that it's hard to leave once you're already in. "If you're man enough to join that club you be man enough to leave that club," he said.
"You came in the front door you go out the front door."
WHERE TO GET HELP:
If you are worried about your or someone else's mental health, the best place to get help is your GP or local mental health provider. However, if you or someone else is in danger or endangering others, call police immediately on 111.
OR IF YOU NEED TO TALK TO SOMEONE ELSE:
• 0800 543 354 (0800 LIFELINE) or free text 4357 (HELP) (available 24/7)
• https://www.lifeline.org.nz/services/suicide-crisis-helpline
• YOUTHLINE: 0800 376 633
• NEED TO TALK? Free call or text 1737 (available 24/7)
• KIDSLINE: 0800 543 754 (available 24/7)
• WHATSUP: 0800 942 8787 (1pm to 11pm)
• DEPRESSION HELPLINE: 0800 111 757 or TEXT 4202
