Barry's character learns about his own motivations for bullying and violence after he is confronted in the play by Eric, Lucy's grandfather, played by Divers.
Divers said 'upstander' was recognised as a modern word meaning an individual who takes a stand against an act of injustice or intolerance, rather than being a bystander.
The play Upstander, like its predecessor Matanui, which was about suicide, is expected to reach several thousand students at nearly 20 schools.
As with Matanui, the students won't just watch the play but can actively help shape the narrative during after-performance workshops.
It follows a two-period programme comprising the play, a Drama in Education workshop and an introduction to community support networks.
Upstander was commissioned by Northland District Health Board with help from Te Puni Kokiri Rangatahi Suicide Prevention Fund.
Matanui, which Divers wrote, directed and acted in, was commissioned by the health board at the end of 2012, in response to the region's youth suicide statistics - the highest in New Zealand at the time.
In 2014 Northland Health boss Nick Chamberlain said that although there had been a marked drop in the region's rates, the board would continue to support youth initiatives aimed at preventing suicide.
Dr Chamberlain said one tool health and youth workers confirmed had played a crucial role in raising awareness was Matanui.
Through its associated subject, Upstander adds to that campaign.
The public can see a free preview of Upstander at 6pm tonightthursday, at 116 Bank St. The play will begin its tour of high schools next week.