Kylie Jenner testified that Tyga told her Blac Chyna slashed him with a knife during an argument

• Kylie Jenner told an LA jury on Monday that she had concerns about her brother's relationship with Blac Chyna.
• The makeup mogul said her ex-boyfriend Tyga told her that Chyna once slashed his arm with a knife.

Kylie Jenner in court on Monday said her ex-boyfriend, the rapper Tyga, once showed her a scar on his arm that he said was the result of his former flame, Blac Chyna, slashing him with a knife during an argument.

The reality TV star and makeup mogul took the stand in a Los Angeles courtroom this week, describing the tense relationship between members of the Kardashian-Jenner clan and Blac Chyna, a former exotic-dancer-turned model, who began dating Rob Kardashian around January 2016.

Chyna, whose legal name is Angela White, is seeking $100 million in damages from the Kardashian-Jenners. She alleges they unfairly trash-talked her to E! Network executives five years ago following her split with Rob Kardashian, leading to the cancellation of her "Keeping Up With The Kardashians" spinoff series, "Rob & Chyna." The Kardashian-Jenners deny these allegations.

By the time Chyna and Rob Kardashian struck up a relationship, the two were already interconnected. Chyna had previously dated Tyga and the two shared a child together named King Cairo. After they broke up, Tyga began dating Rob Kardashian's younger half-sister, Kylie Jenner.

In court on Monday, Lynne Ciani, an attorney for Chyna, pressed Jenner on whether or not she believed Chyna and Tyga had been engaged before their breakup. Media reports from the time described the two as fiancés, but Jenner told the jury that Tyga said he never planned on marrying Chyna.

Jenner said Tyga would frequently discuss "his troubles" with Chyna. She alleged that Tyga showed her a scar on his arm and said Chyna had slashed him with a knife during a heated argument. Jenner also said Tyga told her that Chyna abused alcohol and drugs and may have been intoxicated or high during the incident.

Jenner estimated that the healed scar she observed was approximately 6 inches long, but could not remember on which of Tyga's arms the alleged scar appeared.

Chyna's lawyer asked Jenner if she ever witnessed any other evidence suggesting that Chyna was responsible for inflicting the wound, and Jenner said she had not.

Tyga and Jenner's concerns about Chyna ultimately led them to initiate a conversation with Rob Kardashian about their relationship, she said in court. Jenner said that her brother subsequently told them that he planned to continue his relationship with Chyna anyway.

Monday marked the start of the second week of the trial, which has already elicited several sensational moments following testimony from Chyna, Kardashian-matriarch Kris Jenner, and several others.