So i'm gonna talk about the greatest sibling rivalries of all.
#8 Starfire and Blackfire
Blackfire is just jealous of Starfire.
#7 Splinter and Shredder
Shredder has also forever been jealous of Splinter,Splinter was dating a chick that Shredder had feelings for and well Shredder accidently killed her and kidnapped their daughter, Shredder has also attempted to kill the teenage mutant ninja turtles,Splinter's sons,several times.
#6 Snakeyes and Storm shadow
Storm shadow has been jealous of Snakeyes since they meet because Hard master saw something in Snakeyes that he didn't see in Stormshadow.
#5 Scar and Mufasa
In the classic film the lion king Scar wants to be king but his brother Mufasa,the king,has a son so Scar will never be king right?Wrong Scar kills Mufasa and scare Simba, Mufasa's son out of the kingdom.
#4 Hades,Zeus,and Poseidon
In Percy Jackson;the lighting thief Zeus's lightning bolt was stolen,and he blamed it on Poseidon's son Percy Jackson and threatend to kill his son if he did not return it in a few days,the two were planning war against each after this.Hades abducted Percy's mom and held her hostage so Percy would give him the bolt and he would rule the universe.
#3 Thor and Loki
Loki has always been jealous of Thor,especially when Thor is supposed to become king of Asgard, Loki wants to become king and he tries to kill Thor and Odin alot,Loki also attempts to rule Earth time and time again,Thor loves Earth.
#2 Aqua man and Orm
Orm ,wants to rule Atlantis but Aqua man is the king because Orm is reckless,and arrogant,he also wants to kill Surface dwellers,so Orm tries to kill Aqua man time and time again.
#1 Wolverine and Sadertooth
There are many story lines about the two,and why they hate each other, but I'm going with this one Wolverine hates Sabertooth because on Wolverine's birthday Sabertooth raped and killed Wolverine's girlfriend Silverfox and every year on Wolverine's birthday Sabertooth tracks Wolverine down and battles him to remind him of what he did.