Then let me become a demon

First gen Gu Yue laughed with even more joy; suddenly, he stopped laughing and turned towards Lord Sky Crane, speaking with a voice filled with hatred, "Junior brother, you never thought there would be a day like this, right?! We were both orphans raised by the master. But since young, master always pampered you more. Why? Isn't it because your aptitude is A grade and mine is only C grade?"

"Naturally, with your A grade aptitude, your cultivation progressed much faster. Did you know, with my C grade aptitude, how much sweat and effort I had to put in compared to you, just barely be able to match with your pace? Although we were called the Twin Cranes of Righteous Paths—you were always the main and I the second. You were like the brightest star, just because you were an A grade genius!"