What was supposedly an amicable split, is sure getting nastier and nastier by the day! New details are emerging about Kim Kardashian's "split" -- aka, firing -- of longtime personal assistant Stephanie Shepherd.

Since coming on board with the Queen Kardashian, Steph's job description had grown into something she just wasn't capable of handling, according to some reports. Meanwhile, a RadarOnline report claims, "Kim is telling people that she fired Stephanie because she lacked the mental capacity play a larger role in her brand. But in actuality nothing could be further from the truth.” The source close to Shepherd goes on to say, "Stephanie was tired of being talked to like she was beneath Kim, and she could never do anything for herself because Kim would beg her to stay and work for days on end."

Another report admits Kim and Steph didn't part ways as friends: "Kim made a decision to let Stephanie go. She was a good assistant but when Stephanie wanted to transition into a larger role with Kim’s brand and businesses, it just didn’t work. Kim gave her the chance but after a short period of time it became clear that Stephanie just didn’t have the knowledge to take on a role like that. Kim made an executive decision to part ways," a People magazine source says. "She’s still friendly with the other sisters but she and Kim aren’t really speaking," the source adds.

Shepherd has also been accused of becoming a celebrity herself and not staying out of the spotlight, where Kim may have thought she belonged. But it was Kim who promoted her assistant to COO of Kardashian West brands earlier this year so something dramatic must have happened to make Kim realize Steph wasn't ready for the role. OR something totally unrelated to her business position caused Kim to fire a b*tch.

Shep told Refinery29 for a celeb-assistant profile, "I've never really wanted to be front-and-center on the show. But the thing is, the girls really don't stop living their lives for the camera, so the reality is I'm often there, because I'm actually working." She went on to say, "Sometimes I think about how it’s such a weird thing that people want to know or even care about me, just because I work for Kim. But then it's like, well, she is one of the most recognizable celebrities in the world. I don't get recognized a lot unless I'm with her ..."

Still other rags have another angle on the story, which is that Kim was jealous of Steph's close friendship with Kourtney. They two spent tons of time together and Stephanie even told Refinery29 she gets mistaken for the eldest Kardashian girl because they "look alike" and have "the same style."

So could Kim not handle playing second fiddle to her sis in the eyes of her assistant/COO? Did StephShep get too big for her britches? She does have more than 900K followers on Instagram! But given that her last post with the Kardashian family was on Kendall's birthday a few weeks ago, will fans continue to follow when the Kardashian pix dry up???