But this year, Kim has taken on a more public policy role, cementing her status as an influential political player in her own right. "Prior to this, Kim Yo Jong was portrayed in state media as Kim Jong Un's sister, his protocol officer, or one of his accompanying officials," said Rachel Minyoung Lee, a former North Korea open source intelligence analyst in the U.S. government. "Now, North Koreans know for sure there is more to her than that."
Kim has worked behind the scenes in North Korea's propaganda agencies, a role that led the United States to add her to a list of sanctioned senior officials in 2017 because of human rights abuses and censorship.
In March, state media carried the first ever statement by Kim, in which she criticised South Korean authorities. That was followed by several more, including a response to comments by Trump, and last week, a warning that the North would cut communications with South Korea.
Lee said Kim's statements have a unique style, showcasing her wit and underscoring her powerful position. "In addition to the harsh words and sarcasm, they can be bitingly witty in ways that the other statements are not," Lee said. "She seems to have more leeway in crafting her statements, which of course is not surprising."
When state media announced on Tuesday that the hotlines between North and South Korea would be severed, they said Kim Yo Jong and a longtime hard-liner, Kim Yong Chol, championed the decision at a meeting. This rare explanation of a policymaking process portrayed Kim Yo Jong as "a very substantive person," said Michael Madden, a North Korea leadership expert at the Stimson Centre, a U.S.-based think tank.
Madden said this new portrayal of Kim in state media may be a subtle dig at international analysts who have cast doubts on her ability to wield influence in the North's male-dominated society. "They clearly have high hopes and expectations for her," he said. "Not necessarily the next leader, but something of a king maker nonetheless."
Also read: Migrant crisis: Amitabh Bachchan arranges charter flights for over 500 workers