According to testimony Monday, she expressed concern with her brother Rob Kardashian about his next girlfriend and next-to-be reality TV co-star Blac Chyna, because she had heard Chyna knowingly abuse drugs and alcohol, and become violent, and had gotten a sense of it herself.
"I felt it was my duty to express my concerns," Jenner, who was now 24 and a child at the time, said from the witness stand at a Los Angeles trial. She said her brother didn't follow her warnings, and continued with the relationship.
Chyna is Jenner and three other members of the Kardashian family, alleging they defamed her as violent and forced the cancellation of her reality show, Rob & Chyna, after one brief season.
Both Chyna and Jenner had previously dated Tyga, but Chyna had a child with him. Jenner said Tyga told her dark stories of his relationship with Chyna, showing her a 6-inch knife scar she gave him while abusing drugs and alcohol, according to Jenner.
While she was dating Tyga, Jenner indicated that Chyna had received at least one dangerous text message.
It's weird to say it, because I assumed that she sent me a bunch of devil emojis, and said something like 'counting down the days' until she could beat me or something, she said. I didn't say it, because I assumed it was empty threats.
Jenner said she didn't trust Chyna's love when Rob Kardashian and Chyna began dating in January 2016 and that she did not like her.
I felt like a relationship between the father of her child had something to do with it, and maybe she was out with my brother for other reasons, he said.
Despite her comments, she was cautiously optimistic after they announced in April 2016 that they were getting engaged and in May that they had a baby.
I was happy for my brother at the time, Jenner said, but Im just curious how things will go.
Rob and Chyna would feature in the series in September, and the couple would have a daughter, Dream, in November, and in December, they will have a family-friendly celebration of their show being approved for a second season, which ended in a conflict.
Both Chyna and Jenner's mother said the dispute was profound. when she wrapped a phone-charging cord around her fiance's neck and grabbed his pistol, Kris Jenner said she didn't witness the confrontation, and she was stunned by how violent it might have become.
Kylie Jenner, who lived in the same house as the two, admitted that in the aftermath of the confrontation, she observed some of the damage and remembered her brother being emotionally traumatized, but she did not recall seeing any evidence of physical injury.
According to her testimony, she came away believing that violence had been deadly.
"He used the words, 'She was trying to kill me,' Kylie Jenner said.
On Tuesday, Jenner returns to the witness stand.
Khloe Kardashian and Kim Kardashian are expected to testify later in the week. Kim Kardashian was not in court on Monday for the first time in the six-day trial.
Jeff Olde, who in 2016 served as senior vice president of the E! network, who hosted both Rob & Chyna and Keeping Up With the Kardashians, testified that he approved a second season for the show, although further approval from his bosses would have been required.
He was tense to see additional episodes of the series but decided to include actors getting married.
"I thought it was really rewarding because with a wedding that gave us a hook for season two," said Olde. "Everyone loves a wedding."
Lynne Ciani, Chyna's lawyer, asked Olde about an email he received from Kylie Jenner, expressing concern about Chyna's violent behavior. The email is a key component of Chyna's defamation case.
Olde stated that it did not particularly influence his decision to take a turn on a second season for "Rob & Chyna."
"I don't think it is a direction from 17-year-olds," he said.
He stated that a similar email from Khloe Kardashian shortly after had little impact. He suggested that the show be canceled, but the same person admitted that the couple was no longer a couple.
"It was the Rob and Chyna show, and there were no more Rob and Chyna," said the spokesman. "It was not the show we purchased.."