Kardashian, 30, and Jenner, 20, are suing Chyna for battery, assault and vandalism, Peoplereported.
According to a new lawsuit filed by Kardashian and his half-sister, Chyna attempted to choke her baby's father with an iPhone cord during a fight in late December 2016.
In the complaint filed Wednesday, Kardashian and Jenner reportedly claim they were forced to take legal action against Chyna, 29, after enduring "several months of injuries" after Chyna's "deliberate attempt to extort the Kardashian family for her own monetary gains."
Kardashian and Chyna welcomed a daughter together, Dream Renee, in November of last year, and the complaint accuses Chyna of using Kardashian, saying their relationship was "nothing short of an outright fraud to shake down the Kardashian family."
Kardashian and Jenner reportedly call Chyna a stripper that has "created a reputation as a money-hungry, shameless pseudo-celebrity" in the court documents, adding that she "became extremely intoxicated on drugs and alcohol and physically assaulted" her ex on December 14, 2016.
When recalling the explosive fight that resulted in their split, Kardashian says Chyna "conferenced" his friends on FaceTime "and was carelessly playing with Rob's gun unaware if the gun was loaded or if the safety was on."
Later that night, Kardashian alleges Chyna "lunged towards Rob with an iPhone charging cable and attempted to strangle [him] with the cord around his neck."
The father of one "was able to escape her grasp, however he suffered injuries to his neck," according to People, while Chyna "chased after Rob and repeatedly struck him in the head and face."
The complaint then accuses Chyna of having pursued Rob outside the house as he tried to escape in his Bentley, which prompted Chyna to throw "a nearby chair at Rob's car causing damage to the vehicle and also used a metal rod to injure Rob."
Not only is Kardashian claiming he suffered neck injuries during the argument, but he's alleging Chyna also damaged a television, broke down a door, damaged the walls of the home, and destroyed cell phones in the house.
Jenner wrote in the court papers that damages to her house were in excess of $100,000, People reported.
Jenner also alleges Chyna personally "terrorized" her by "telling her to get tests for sexually transmitted diseases" when she was in a relationship with Chyna's ex, rapper Tyga. (Tyga is also the father of Chyna's first child, a son named King Cairo).
"[Chyna] would threaten to beat up Rob's sisters and was disrespectful towards Rob's mother [Kris Jenner]," the lawsuit reads.
A source close to Chyna, however, insisted to People the explosive fight between the model and Kardashian was "not a real thing."
"It makes sense on their part to come up with a counter claim for the very real claim made against him," the source said, referring to how Kardashian had been accused of posting "revenge porn" on social media following his breakup with Chyna.
In early July, Kardashian accused Chyna of being a gold digger, abusing alcohol, doing drugs, and cheating with as many as seven male sexual partners "in less than a month." Chyna, in turn, alleged that Kardashian both verbally and physically abused her, and she was granted a restraining order later that month.
"Revenge porn, posting naked pictures to 9 million people across the world," the source continued. "None of that compares to an altercation that they got into at Kylie's house. They're so miles apart and it really distracts from the real sexual and domestic abuse that took place."
The source added that Kardashian should've raised the issue in December if the situation was so serious rather than waited until now to take legal action against Chyna.