My grandfather was a Nazi executioner at Auschwitz — and I had no idea until 7th grade history class

In a Stuttgart classroom in the 1970s, seventh-grader Kai Höss learned something that would change his life.

A teacher was reading from a history textbook about the Holocaust when the name “Rudolf Höss” came up.

Kai went home and asked his mother if there was any relation. She confirmed that Rudolf was his grandfather — and a Nazi SS officer and Auschwitz commandant who was responsible for the deaths of 1.1 million people, mostly Jews.

“I just felt ashamed,” Kai told The Post of learning the horrible truth about his father’s father.

Rudolf personally ordered subordinates to herd prisoners into the “showers” where lethal clouds of poison Zyklon-B gas were released. He was captured in 1946 and confessed to killing 2,000 people hourly in gas chambers. Polish authorities executed him in 1947 at Auschwitz.

“[Our] name is synonymous with incredible crimes against humanity and atrocities and the Holocaust and antisemitism,” Kai said.

Now 63 and a Christian pastor still based in Stuttgart, he has made it his mission to support Jewish communities, promote reconciliation and educate people about the Holocaust.

The passage of 80 years since the end of World War II, he said, and a contemporary culture now saturated with violent video games has “desensitized” people, especially young adults, to the past, he believes.

“We need to bring people back to see what happened in Auschwitz and in Nazi Germany, what they did, how inhumane, how horrible this was,” Kai said. “People can study all the historical facts and the statistics, but they need to have tears.”

His mother, Hedwig, only learned of Rudolf’s crimes five years into her marriage to one of his sons, Hans-Jürgen Höss. He dismissed it as “water under the bridge,” but his silence poisoned the home.

Hans-Jürgen left his mother when Kai was in his 20s for another woman, and they had a violent clash in which she stabbed him with a dagger-like letter opener that had belonged to Rudolf.

“My mother’s heartbreak turned to wrath,” Kai recalled. “She almost murdered him.”

Kai wasn’t initially a religious man. Early in his career, he worked in the hospitality industry in luxury hotels across Africa, the Middle East, and Asia. A near-fatal tonsillectomy in the 1980s led him to Christianity.

He now lectures on the Holocaust and visits synagogues in Europe, America and, soon, Australia, sharing his redemption story.

A few years back, Kai reunited with his father, who had remarried and moved to Germany’s Baltic Sea coast. The two are featured in a recent HBO documentary, “The Commandant’s Shadow,” which was just nominated for a 2025 Emmy Award for “Best Documentary.”

It details Rudolf’s crimes through his autobiography, read partly by Hans-Jürgen, and shows Kai and his father meeting Auschwitz survivor Anita Lasker-Wallfisch and her daughter, Maya, a psychotherapist.

“She was one of the people that suffered under this machine that [my grandfather] created,” Kai said of Anita.

Now 99-years-old and living in London, she survived Auschwitz thanks to her musical talent, which earned her a spot in the women’s orchestra playing cello.

Their meeting was an emotional one, filmed in Anita’s flat.

It was about “morality,” not just an apology, Maya said. “[Hans-Jürgen] sufficiently took the opportunity in a very dignified manner which he needed to, not because he was responsible [for Auschwitz, but] because he was responsible for acknowledging the truth he did.”

Hans-Jürgen passed away in December from pneumonia Kai is grateful they were able to connect with Anita before he died.

“It was just a wonderful blessing and experience to be there, to meet that woman, who actually was hurt so much, when you think a whole family was exterminated in Auschwitz and she suffered,” he said.

Holocaust experts laud Kai’s efforts to acknowledge his family’s past and educate others.

“With the rise of antisemitism, It’s brave of him to be doing this,” said Trisha Posner, author of “The Pharmacist of Auschwitz.” It’s a very sensitive period we’re in at the moment … with the denial of the Holocaust [and] the denial of October the seventh.”

Gerald Posner, her husband and the author of “Hitler’s Children,” a book about Nazi officials’ offspring, noted that Kai could have just ignored his family’s ugly ties.

“It would have been very easy for him to have said, ‘Well, you know, I have nothing to do with him, and just gone on with his life.”

Rabbi Abraham Cooper of the Simon Wiesenthal Center is grateful he didn’t.

“To have someone with that last name stepping forward and saying, ‘I’m leading a different life and different commitments,’ it does make a difference,” he said.

For Kai, it all comes down to making sure people really grapple with recent history and not just coldly intellectualize the past.

He said, “We have to move people’s knowledge six inches down, from the head to the heart.”