TOKYO -- Just two years ago, Kim Yo Jong, the sister of North Korean leader Kim Jong Un, won many hearts at the Pyeongchang Winter Olympics with her smile diplomacy.
South Korean progressives, who had applauded her as a "messenger of peace" back then, are devastated by the recent turn of events.
While her all-powerful brother has been in and out of the spotlight since returning from a conspicuous absence in April and May, it has been Kim Yo Jong who has been the face of the North Korean leadership, as it takes an increasingly hostile stance toward the South.
On Tuesday, just as Yo Jong had predicted days earlier, the inter-Korean liaison office in the North Korean border town of Kaesong was destroyed.
In a statement released Saturday, Yo Jong had made clear that she was empowered to take critical decisions. "By exercising my power authorized by the Supreme Leader, our Party and the state, I gave an instruction to the arms of the department in charge of the affairs with enemy to decisively carry out the next action," she said.
Under those instructions from Yo Jong, the military said Wednesday it will deploy troops to two joint economic projects with the South -- the Mt. Kumgang tourist area and the Kaesong Industrial Zone.
Kim Yo Jong's sudden emergence, as well as her intensified rhetoric against Seoul, has sparked speculation that her brother is now grooming her as a potential successor.
The 32-year-old granddaughter of founding father Kim Il Sung and daughter of former leader Kim Jong Il previously worked as an official at North Korea's Propaganda and Agitation Department. It was reported recently that she has taken charge of North-South relations.
The heightened tensions on the Korean Peninsula represent a major test for her.
When Kim Jong Un's health was in question earlier this year, many experts dismissed Kim Yo Jong as a serious contender -- despite her coming from the Kim family -- due to the country's deeply patriarchal values. The military would not accept a female leader, especially one so young, they said.
"In North Korea, it's the military that carries clout in an emergency," said a former official for the ruling Workers' Party of Korea. "A woman will have a hard time as leader."
When Kim Jong Il first became leader, taking control of the military was his top priority. His son, Kim Jong Un, was appointed vice chairman of the Workers' Party Central Military Commission before he was formally announced as the future leader. He accompanied his father to inspect troops.
Kim Yo Jong has no military record, nor is she a member of the Central Military Commission. It seems unlikely that she could lead North Korea and its roughly 1.2 million-member military without bolstering her resume.
Even if she became leader, the military could stage a coup during an emergency, the former Workers' Party official said.
Chinese founding father Mao Zedong once said that "political power grows out of the barrel of a gun." This has been true in North Korea, where the military predates the country itself. Any armed action ordered by Kim Yo Jong will help demonstrate her influence over the military and boost her credibility as a potential heir to her brother.
Kim Jong Un himself was required to prove his military mettle in 2010, shortly after he was designated his father's successor, with the shelling the South Korean island of Yeonpyeong. The incident killed four and is reportedly considered one of his key achievements in the North. Concerns exist that Pyongyang plans a similar military attack, this time to boost Kim Yo Jong's profile.
Kim Jong Un is believed to be pulling the strings behind his sister's recent rise. Given that his three children are all younger than 10, he could be helping Kim Yo Jong address her weaknesses in case she has to take the country's reins.
Boosting his sister's influence also helps Kim Jong Un strengthen his own grip on power. Kim Yo Jong is one of the few people, if not the only person, whom the North Korean leader trusts. Speculation over his health has persisted despite his sporadic public appearances in recent months.