Kardashians Exposed: Inside the Instagram Feud Between Rob Kardashian and Kim Kardashian

Just days after blasting his sister Kim Kardashian on Instagram, more details have emerged about Rob Kardashian's shocking diss.

The reality TV star shocked the world when he posted a picture of Rosamund Pike covered in blood, in character in her hit film Gone Girl, and wrote in the caption "This is my sister kim , the b*tch from Gone Girl,,,"

This is my sister kim , the bitch from Gone Girl,,,

A photo posted by ROBERT KARDASHIAN (@robkardashian) on Mar 22, 2015 at 10:38am PDT

But the revelation didn't come out of nowhere. MStarNews has learned that the fued between Kim and Rob has been brewing for months because Rob believes that Kim is the "puppet master" that controls the whole family.

According to Rob, Kim "controls the whole family and wants the world to think that their world is perfect."

The two haven't been getting along for a while now. Kim reportedly thinks that Rob is lazy and "bringing down the family name" because of his overweight appearance.  Rob also abruptly left Kim and Kanye West's French wedding last summer.  The two reportedly got into an argument during which Kim accused Rob of leaking negative stories about her to press.

"That was the final straw for Rob, because that was something he would never do," a source told Radar Online.

The two haven't been on speaking terms since, says a source.

A source close to the Kardashian family told People Magazine that the whole family thinks the stunt was "so dumb."

"He always posts things he thinks are funny and deletes and unfollows people," the source said. "He's so bizarre, he posts and deletes and thinks people aren't going to notice. He's been depressed and just a bit off in general."

But so far, no one in the family seems phased. No one has commented publicly, and it seems like Rob has been solidly ostracized from the family.

"The family is just doing their own thing, and no one besides Khloe is truly concerned for Rob," said a source. "Kourtney is raising three kids and her baby daddy Scott Disick is a mess. Kendall and Kylie are teenagers, and living their own lives. Kim is to busy taking selfies, dyeing her hair, and shopping to care about anything more in her life, even Rob!"