The reality star also opens up about the "healing experience" at her husband's Sunday Services.
In a new interview with Elle, Kim revealed how North talked her younger brother into helping her with an elaborate April Fools' Day prank that was surprisingly dark, but also left their mama feeling just "a little impressed."
Admitting she does worry about her children "getting along," Kardashian explained they are "starting to get a little closer now that she can include him in her jokes."
"She roped him into an April Fools' prank yesterday that was ridiculous," explained Kim. "She took ketchup into my bathroom, and she begged me to let her spread it on me, and on the bathroom, as if it was like a bad scary movie. Then she asked me to lie down. I thought she was just playing, maybe that she was going to say I was hurt."
"No. She taught Saint how to fake-cry -- she showed him how to do it -- and then she told him to scream 'Mommy's dead!'" Kim continued. "Kanye ran upstairs and he was like, 'Kids, this is not funny. This is not a good prank.' I completely understand and I agree."
She did concede that she was also "a little impressed" by the stunt though, because "they planned something together, and they were getting along and having fun as a team."
North has definitely been coming out of her shell as she gets older, as the 5-year-old continues to steal the spotlight with her dance moves at Kanye's weekly Sunday Services.
Speaking with Elle, Kim was also asked about the weekly gatherings, which include a massive gospel choir and more than a few celebrity guests. The publication noted that Kim's publicist initially shut down the question, but Kardashian was more than happy to talk.
"It's honestly more like a healing experience for my husband," she said. "It's just music; there's no sermon. It's definitely something he believes in -- Jesus -- and there's a Christian vibe. But there's no preaching. It's just a very spiritual Christian experience."
Kardashian added that her family's friends of many different faiths attend and leave loving it. "Everyone that comes understands it's just a really healing experience with an amazing choir," she said, "and amazing messages about love to start off your week."
Kanye will be bringing his service to Coachella this year, with a special performance on Easter Sunday.