I don't think scars side got touched by the light.
So technically, He already was a king in a way.
And technically he didn't need to kill mufasa
Man years later and I'm still realizing how petty he was. (Not even adding to the fact he didn't do much hunting or anything after he got to be king lol)
This made me think "Everything the light touches is ours" I don't think scars side got touched by