Raoul Craemer never met his paternal grandfather. He doesn't even know much about the man, since his own father never got to know him and his grandmother wouldn't talk much about him.

Craemer's grandfather was a German lawyer who fought in World War II, returned to the front twice after being wounded and died in action. He was posthumously appointed a judge by Adolf Hitler – presumably, Craemer says, in recognition of his loyalty and as a way to grant his survivors a pension. But much about him remains a mystery.

"We don't know if he was SS, nobody will tell us. My grandmother won't talk any specifics. It's a great shame of the Germans."

Craemer poured his feelings and his research into his family's history into Pigman's Lament, the third play he has written and the second solo show he has acted in after his 2012 Green Room Award-winning turn in Kabir by Canberra playwright Subhash Jaireth.

"I worked in the Hive program of the Street Theatre. The play was developed with dramaturg Peter Matheson, who was resident dramaturg at the Melbourne Theatre Company for 15 years then went freelance."

The writing and development process lasted a few years as the play underwent 20 drafts and many changes.

"I started off with seven characters and ended up with just two."

Those two characters, both played by Craemer, are "himself" – the playwright, a modern house husband, writer and actor – and his grandfather, who confronts him one night in what becomes a battle of wills and wits between the two men. Craemer describes it as a psychological thriller in which their very different perspectives and lives come into conflict.

He thinks his grandfather – "an upstanding German patriotic guy" – would despise his mixed-race, German-Indian grandson and the way he lives: an unmarried spouse and father whose partner is the main moneyearner in the relationship. And instead of a steady job, Craemer has set up his life so he can take on professional acting jobs.

"He wouldn't approve of anything in the set-up."

But the disapprobation and pushing on pressure points doesn't all go one way, with "Craemer" bringing up the past and accusing his grandfather of family secrets he doesn't want to become public.

"The music is by Lara Soulio and Sianna Lee. They are two young women from Melbourne who agreed to collaborate with us due to their previous work with Paulo Castro," Craemer says.

"It's quite scary and atmospheric and filmic."

The collaborative process also extended to the other members of the creative team, especially Portuguese-born Adelaide director Paulo Castro.

"I can't emphasise enough how important Paulo's direction has been to bring this play to life. He's amazing."

Craemer worked closely and collaboratively with Castro, particularly in delineating the two characters. The audience might see him as mad at first, he says, but the nature of the piece will become clear as it unfolds, with dark humour and some surprises along the way.

Apart from his family's history, Craemer was inspired by the in-your-face performance art work of artist Otto Muehl, one of the proponents of Viennese Actionism, particularly in the actor's transformation into a "pigman" during the play.

He says, "I guess the pig works on multiple levels: for example, 'he's a pig'; the pigman from Minecraft, half pixelated, is interesting in that it sort of is a half-realised man; the fact that pigs are one of the few animals that will completely devour a man (including bones, I'm told!); and there's also an anecdote from my youth when I was at Otto Muehl's commune and they did a pig performance and also killed a pig. So yeah, it kind of felt appropriate!"