The daughter of a shadowy religious figure, Choi Soon-sil has been at the side of now-ousted South Korean president Park Geun-hye for decades, bound to the politician by her father.
Now Choi, 61, may spend the rest of her life in prison after being jailed for 20 years for her role in the epic corruption scandal that rocked the nation and brought down her lifelong friend.
Choi's father Choi Tae-min made the first connection to Park decades ago.
When Park's mother was assassinated in 1974 in a failed attempt to kill her dictator father Park Chung-hee, Choi Tae-min sent the future president a letter claiming he had seen her mother in his dreams.
The senior Choi, 40 years older than Park and the seven-times-married founder of a cult-like group, won her trust. His influence grew after Park's father was himself shot dead in 1979 and she became a recluse.
A later US diplomatic cable published by Wikileaks noted widespread rumours that Choi Tae-min had "complete control over Park's body and soul".
His daughter Soon-sil became a close friend of Park's, handling numerous aspects of her daily life even down to her wardrobe choices.
In 1990 Park's sister and brother sent then-President Roh Tae-woo a letter pleading for him to "rescue" their sibling from Choi Tae-min and his relatives.
The Choi clan sought to profit from their connection to Park and persuaded her to cut all contact with her siblings, according to sister Park Geun-Ryoung.
Choi Tae-min died in 1994 but Soon-sil inherited his guiding role.
Three years later Park entered politics, winning a seat in parliament.
- 'Vulgar and greedy' -
By the time Park was elected president in 2012 and moved into the Blue House she relied heavily on Choi for decisions over policy and personnel, according to a probe by prosecutors last year.
Choi had no title or security clearance, and remained largely unknown to the public. But recorded phone conversations released by prosecutors during Park's own trial revealed Choi giving orders regarding policy directives or PR campaigns at the presidential office.
Choi was heard constantly asking a key aide to Park, "Did you write down what I just said?" or admonishing him, "Why didn't you do that last time?" -- while the official spoke in the respectful Korean language terms usually reserved to address superiors.
Along the way, prosecutors say, she used her influence on Park to force major Seoul firms including Samsung to donate tens of millions of dollars to non-profit foundations which she allegedly used for personal gain.
The ties finally came to light in late 2016 when a Seoul TV station obtained Choi's tablet computer -- ostensibly when a reporter found it in an abandoned office -- containing many confidential presidential documents, including drafts of Park's speeches.
Choi tearfully apologised when she was summoned by prosecutors in October 2016 -- her first public appearance -- as the fury over the scandal sparked nationwide protests urging Park's ousting.
But she later denied all charges against her, saying she had little influence over Park.
For her part the former president -- who is on trial separately and denies all the charges against her -- publicly apologised for "overtrusting" Choi.
Ex-lawmaker Chun Yu-Ok, a former spokeswoman for Park's party and once a close ally of Park, described the Choi clan as "vulgar, greedy and sleazy" in a recent book on her experiences in politics.
Chun cut ties with Park in 2007, and slammed her as "someone who should never be president" during Park's victorious election campaign five years later.
She feared that if Park became head of state, "the country would be ruled by the collective leadership of the Choi clan", the former journalist wrote.
"I hoped my fear would prove to be wrong, but unfortunately it turned out to be correct -- a big tragedy for our country."
"They were people of the darkness."