If you have ever had a brother or a sister, you have likely been in a few fights with them growing up. All siblings go through this with each other. It is just a fact that sisters fight sisters, brothers fight brothers and sisters as well.
Take the Kardashian's for example, Khloe, Kim, and Kourtney have definitely been in sisterly spats plenty of times. It is just the way siblings act toward each other. However, one thing about Brody Jenner, he has never been included in with either side of the family. So, who is Brody Jenner and how is he related to the KarJenner family?