"Evil monster, murderer, Nazi," - that's how Henrik Lenkeit describes his grandfather.
It sounds extreme until you discover that the man he's referring to was the ruthless Nazi leader Heinrich Himmler.
Hitler's right-hand man, Himmler was a feared and fanatical man known for his leading role in the Final Solution and Holocaust.
So, imagine how Henrik felt when aged 47 he discovered by chance that they were related.
Carefully, he recounts the moment in 2024 which would change his life forever.
He explains he'd been restless for most of the day so started watching a documentary about the Nazis online.
Interested in what he had seen, he took to the internet to find out more.
But when he opened one website, the face of his maternal grandmother, Hedwig Potthast, stared back.
Beneath it a label said, "Himmler's mistress".
Further research revealed Himmler was his mother's biological father and Henrik's grandfather.
"How do you process that you're related to one of the biggest criminals in history?" I ask during our meeting in Berlin.
"You don't," Henrik quickly replies.
He says the discovery prompted him to ask a string of questions about everything he thought he knew.
"Who am I? Who was I? Why wasn't I told the truth for 47 years?" he says.
"After 47 years, my life was like a lie," he adds.
While he doesn't have a definitive answer, he believes his parents shielded him from the truth to protect him.
He opens a photo album and shows me photos of Hedwig.
It's 1935 and she's young at the time and smiling slightly.
By 1938, Henrik says she and Himmler had confessed their love for each other.
They had met through work at the notorious secret police headquarters in Berlin, where she was employed as his private secretary.
It wasn't long before they began their affair.
"She was a friendly person," Henrik says as he thinks about the woman he used to call "Mutti," an affectionate term meaning mother.
"I've never thought she could be the mistress of a mass murderer. Knowing that, of course, was a shock," he adds.
During research for the interview, I read that Potthast was a convinced by Nazi.
One article even claimed she had had a copy of Adolf Hitler's notorious book "Mein Kampf" bound with human skin.
I ask Henrik if he's heard about this?
"She knew. I think she knew everything," he says, dispelling any idea she was a naive young woman somehow oblivious to her lover's horrors.
"They were lovers. Monster lovers. I even heard that she encouraged Himmler to accelerate." Henrik says.
Letters between the pair show Himmler affectionately referring to Hedwig as "bunny."
In one, he signs off "with endless fond thoughts and greetings."
Despite being married to someone else when Henrik's grandmother got pregnant, Himmler believed he was spreading the master race and therefore had his name added to Henrik's mother's birth certificate.
His blood tie with Henrik is confirmed in black and white.
I ask him if that genetic link frightens him.
"Of course. You ask yourself, 'What is my inheritance from that?'" Henrik replies.
The head of the SS death squad, Himmler was a principal architect of the extermination camps under the so-called Final Solution, a Nazi term for the deliberate and systematic genocide of European Jews.
They created sprawling camps designed for death where millions of people, mainly Jews, were murdered.
Given the extent of his crimes, I'm interested to hear how Henrik views Himmler now he knows about their relationship.
"Mass murderer," "devil," "demon," are some of the words he comes up with.
"All the bad things you can imagine," he adds.
"And then you have to put grandfather on the end of that list," I reply.
"Yeah, Hitler's deputy and grandfather," he says, slowly. "He is my grandfather. I can't do anything about that."
While he can't change his heritage, Henrik wants to ask Himmler's victims for forgiveness and fully divorce himself from his grandfather's dark past.
(c) Sky News 2025: Heinrich Himmler: Man discovers architect of the Holocaust was his grandfather

Christmas Day shooting leaves man fighting for life
Thailand and Cambodia sign ceasefire agreement after weeks of intense fighting
Trump's claim US airstrikes in Nigeria hit ISIS targets 'sketchy', presidential adviser tells Sky News
Details of military gap year for UK's under 25s revealed
TUC leader: Sir Keir Starmer must tackle cost-of-living crisis to counter 'real danger' of Reform
One of the men who went missing in sea off Devon coast named
UK pension funds eye stake in £4.5bn holiday giant Center Parcs
Clinton told to avoid public handshake with Gerry Adams, records show