Premise: We all know Scar is jealous of Mufasa because he [Scar] wouldn't become king, plus Simba is in the way. But is there another reason?
Chapter 1: A Secret Inside
Before Scar got his name because of his scar on his left eye, Scar was known as Prince Taka. He was the second son of Ahadi and Uru, second king and queen of Pride Rock.
Taka, at first, loved his brother very much, and had no jealousy of him whatsoever. Until now.
Taka secretly followed his father, Ahadi, bringing Mufasa to the grasslands 15-20 feet from Pride Rock.
And Taka overheard his father and his brother talk about being king.
"Mufasa, you are in royal blood of the Pride. And since you are the oldest, you will be the next king after me. You must take responsibility over the things you possess once you are king. One day I won't be here, so I always take my chances to give wisdom to you and your brother. The same goes for your mother. I want great joy, peace, and harmony in this family and families to come. So promise me, Mufasa. Promise me you will take my place in the right way." Ahadi said to Mufasa.
"I promise, father." Mufasa said.
Taka left running away from the sight of his father and brother, quietly bursting into tears.
Then he found himself meeting a young lioness, a little younger than him, walking around the greenest part of the Pride lands.
"Hello, Prince Taka. My name is Zira. Why are you drowned in your tears of sorrow, young Prince." Zira said. Zira had a great deal of figurative speech when she was growing up.
"I'm not going to be king. I heard my father say Mufasa will be next in line. It's not fair!" Taka grumbled in tears.
But Zira was there to comfort him. But tought a bad lesson:
"Your father chose your older brother instead of you? Who is that worth loving?" Zira said.
Blinded by his jealousy Taka said: "You're right. Who is that worth loving and caring for, and they just care for the older one."
And that, in his heart, became jealousy and anger.
A few minutes later...
Taka returned to Pride Rock, having a blank face, but with a touch of despise when Mufasa looked at him.
"Mother, when will we eat supper?' Taka asked his mother, Uru.
"Supper. Supper! Oh my goodness, time to hunt! Thank you, my son for reminding me. I'll be back as soon as I get enough for all of us. Good-bye!" Uru said, a little rushed and stressed.
A few minutes later...again...
Uru came back a with a mouthful of antelope. She brought in two, more than enough for the whole family.
"Taka! Mufasa! Ahadi! Supper has arrived!" Uru called through Pride Rock.
The family happily, except for Taka, ate antelope and soon, their stomachs were full.
After supper Taka immediately went to his room. The family notices he's been acting strange, so Mufasa decides to talk to him.
"Taka, my brother. Why are you acting so strange?" Mufasa asked.
But Taka refused to answer. He just turned his head away from his brother.
"Brother, why won't you tell me?"
"You wouldn't like it." Taka responded.
"Hey, Taka. We're brothers, and brothers are inseperable. Whether either of us likes it or not, you're there for me, and I for you."
This made Taka's jealousy soften a little. So Taka told Mufasa [half of] the truth. And Mufasa didn't like it, but he was there for his brother.
"Taka, you did good today." Mufasa said as he left.