Kang Chun-hyok poses for a portrait in front of his artworks, which describe his childhood in North Korea, at Gallery IS on Aug 6. in Seoul. (Shin Woong-jae/For The Washington Post)

— Most rap songs do not deal with matters of geopolitical significance — such as nuclear weapons and labor camps — but Kang Chun-hyok is not most rappers. The 29-year-old is an escapee from North Korea, where the most boundary-pushing music is revolutionary opera extolling the virtues of Kim Il Sung, the country’s founder.

Now, Kang wants to be the greatest rapper North Korea has ever produced. With a lack of rivals to the title, he may well be able to claim it.

“You took money that we made digging earth to fund nuclear weapons. Take out that fat from your pot belly. Nuclear weapons. Nuclear weapons,” he rapped at the opening of an exhibition in Seoul this month titled “Kkotjebi in Bloom.”

Kang also had artwork on display in the exhibition, organized by the Citizens’ Alliance for North Korean Human Rights, a nongovernmental organization, to draw attention to the hardships that children in North Korea face.

“I am not afraid. Go ahead, attack me,” Kang continued, moving his right hand Eminem-style. His trendily askew baseball cap read “Own It All,” while his Nike T-shirt exhorted: “Man Up or Shut Up.”

“Give me back that dirtied money. Show me the money,” he concluded, to cheers from the humanitarian workers, foreign diplomats and academics in the gallery, and from people who happened to be walking along Insadong-gil, a central Seoul street lined with art galleries and tourist shops.

Kang is one of a generation of North Korean defectors coming of age and finding his voice in South Korea. And his triumph is even more noteworthy given that he was a kkot-jebi, or “flowering swallow,” the term used in North Korea for homeless children, a reference to their constant hunt for food and shelter.

About 25,000 North Koreans have escaped to the South over the past two decades. The first wave of defectors tended to be high-ranking officials who were treated like royalty in the South, mined for information about Kim Jong Il’s regime.

But then thousands who were not considered so valuable in the South’s eyes started arriving, including many 20- and 30-somethings from the impoverished northern provinces of North Korea. They had no useful information about Kim and his cronies, spoke with country-bumpkin accents, and didn’t know how to use credit cards or smartphones — essentials of life in the South.

But their children have grown up in South Korea and have been able to integrate more easily.

“These are people who came here 10 years ago and are the first wave of high school and university graduates,” said Joanna Hosaniak, deputy director general of the Citizens’ Alliance for North Korean Human Rights. “Now they’re writing books, painting, showing leadership in their own areas. They’re like eggs that are hatching.”

That applies even to the most disadvantaged of North Korean children — the kkot-jebi. In the North, these children survive by begging and scrounging for food, and can often be seen sleeping around train stations.

The problem of homeless children was particularly severe in the first decade of the 21st century, after a devastating famine in the 1990s caused thousands, perhaps millions, of North Koreans to die of starvation or flee across the border to China. Many left behind children who had no choice but to fend for themselves.

While malnutrition is still common in North Korea, starvation is not. That means there are fewer traditional kkot-jebi in the closed state, but new categories of “swallows” are emerging. Today, North Koreans talk about the other “swallows” who have flown away: the gun-jebi, who have left the military; the chong-jebi (young adults) and noh-jebi (elderly people) who are living on the streets. There are even whole families — kachok-jebi — leaving their homes to look for food.

As many as 2 million people in North Korea — a tenth of the population — are homeless, says Kim Hyuk, a former kkot-jebi who has written a memoir, “The Boy Who Stole Freedom.”

“People now have more flexibility because the state can’t provide for them,” said Kim, who is enrolled in a doctoral program in North Korean policy at a South Korean institute.

Kang ran away from his home in a northern North Korean province at age 13 after discovering that the woman whom he thought was his mother was not. He arrived in the South three years later, in 2001. He is now in his senior year as a fine-arts major at Hongik University, one of the South’s top creative colleges.

A set of his drawings — illustrations for a Southern children’s book called “Do You Know How Happy You Are?” — shows skinny kids in tattered clothing searching for food and sleeping on the street.

In addition to his art, Kang has been working on his singing to promote awareness of what is happening north of the border.

A well-known South Korean hip-hop artist, Yang Dong-geun — also called YDG — has volunteered to teach Kang how to rap, and supporters started a crowdfunding campaign to help launch his musical career.

“People here don’t know anything about what’s going on in North Korea,” Kang said in an interview at the exhibition, “so I’m trying to show what is really happening there.”