DiipuSurotu
Banned
http://lionking.wikia.com/wiki/Original_Concepts_and_Documentations#Scar
”Because originally, Scar was a rogue lion. He didn't have anything to do with the pride, and then we thought, 'Well...it'd be more interesting if the threat came from within.'"
—Roger Allers[19]
It was mentioned by Roger Allers, the co-director of The Lion King, in one of the documentation videos that Scar originally had no relation to the royal family but still desired the throne. After Jeremy Irons' features were worked into Scar, he was changed to be Mufasa's brother because the thought of an "inside threat" was a lot more interesting than a random rogue. This is why Scar and Mufasa differ so much in appearance, despite being full brothers.