Kim Yo Jong appears to be stepping out on her own recently — without her elder brother, North Korean leader Kim Jong Un by her side — which analysts said may indicate that she could be moving into a bigger role within the country's leadership structure.
In the last week, Pyongyang has issued threats and directives under the younger Kim's name alone — a development analysts said was striking.
"We're seeing a lot of big statements coming out of Kim Yo Jong," said John Park, director of the Korea Project at the Harvard Kennedy School. This indicates that her role is not just ceremonial and that she has been "chronically underestimated," he added.
The elder Kim sibling's complete absence is particularly significant, said Miha Hribernik, head of Asia, risk insight at Verisk Maplecroft.
"By letting his sister Kim Yo-jong lead the highly visible charge against the South, he is likely laying the groundwork for her elevation to a more senior position within the regime," Hribernik wrote in a note this week before North Korea blew up its joint liaison office with South Korea.
There's precedent for this since Kim Jong Un notably led the bombardment of South Korea's Yeonpyeong Island in 2010 in order to boost his standing with the military before taking over as Supreme Leader in 2011, Hribernik noted.
Little is known about Kim Yo Jong, but it is well documented that she spent some time in Switzerland with her brother Kim Jong Un. Both were born to the same mother, a consort to the late North Korean leader Kim Jong Il.
Analysts say the siblings living together for a number of years in the same place outside their home country has fostered close ties between the two and that is now manifesting in the younger sister's elevation on a political level.
"I think what we're seeing now is essentially a reflection of a partnership that she has with her brother," said Park. "It looks like there is this kind of power partnership between the two that became more visible."
The younger Kim first came into the global limelight when she attended the opening ceremony of the 2018 Pyeongchang Winter Olympics. This made her the first from the Kim family to set foot in South Korea.
Later, the younger Kim accompanied her brother when he attended summits with South Korean President Moon Jae-in, U.S. President Donald Trump and Chinese President Xi Jinping.
Although the younger Kim is a known factor and has been the de facto number two in North Korea for several years, she only began to assert herself this past March, said Lee Sung Yoon, Kim Koo-Korea Foundation Professor of Korean Studies at The Fletcher School at Tufts University.
That month she issued a letter in her own name ridiculing the South Korean presidential office and another acknowledging U.S. President Donald Trump's letter to her brother, signaling to "the world she is in charge of foreign policy," said Lee.
And with the bombing of the joint office coming days after Kim Yo Jong warned about it, "she's showing that she is in charge and that she is a hardnose North Korean leader," said Lee.
While it's interesting that the younger Kim sibling has been "given the megaphone" to deliver the threat this time, that may also mean that tensions may grow on the Korean peninsula said Jung Pak, the SK-Korea Foundation Chair in Korea Studies at Brookings Institution's Center for East Asia Policy Studies.
"If this is intended to give her military credentials which was a gaping hole in her resume, then we might be seeing additional provocative action and manufactured crisis that end up in a military clash," Pak told CNBC.