Kim Jong Un’s sister is on the rise.

Kim Yo Jong first attracted attention when she attended her father Kim Jong Il’s funeral in December 2011 and later when she appeared next to her brother on election day in March 2014. The latter event in particular triggered speculation that Kim Yo Jong was on the rise within the regime called the Democratic People’s Republic of Korea (DPRK).

That speculation proved correct when the state media account of Kim Jong Un’s visit to a cartoon studio was released on November 26, 2014, listing Kim Yo Jong as “vice department director” in the powerful Central Committee of the ruling Worker’s Party.

Daily Mail further speculates that Kim Yo Jong, as vice department director, is being groomed for a position as a key aide to her brother but emphasizes that the responsibilities of the vice department director are not exactly clear.

As Kim Yo Jong’s appearances have increased, experts have been trying to piece together what she does within the regime. She has been pictured several times within her brother’s company on “field guidance tours,” which have led to speculation that she is like an event director or manages her brother’s personal schedule.

“She may be one of the only people Kim Jong Un trusts completely,” Madden said.

Experts believe that Kim Yo Jong was born in 1987 or 1988, making her 26 or 27 years old, and that she is close to her brother Kim Jong Un. While their father and former dictator Kim Jong Il fathered at least seven children by four different women, experts believe Kim Yo Jong and her Kim Jong Un have the same parentage.

Michael Madden, founder of North Korea Leadership Watch, says that the two siblings were raised by their mother Ko Young Hui at a hillside estate, where they were acquainted with, for the most part, family members and close friends.

“As they say in [Martin Scorsese’s mafia epic] Goodfellas, ‘There were never any outsiders,’” Madden said to Time Magazine. “The life of Kim children was hermetically sealed.”

“The old power elites loyal to Kim Jong Il are being pushed out,” said Yang Moo-jin, a professor at Seoul’s University of North Korean Studies, in an interview to Time earlier this year. “They will be replaced by new, younger elites who can safeguard the leadership of Kim Jong Un.”