Disciples Shen Jiu and Shen Yuan are constantly on the same wavelength, and they both hate it.
Shen Jiu thinks he's supposed to be so much smarter than Shen Yuan. He's clever, and ruthless, and always three steps ahead of his opponent, so how the hell is this flighty, spoiled little twink lordling with his head in the clouds and his nose in a book always able to see through his schemes?
Meanwhile, Shen Yuan is supposed to be better than the Scum Villain! He's not perfect, no one is, but he's not like that cruel, sadistic, mean-spirited asshole! (Huh? What about his comment history? Cheering for torture and dismemberment is different, okay, he was just saying what everyone was else thinking! (They weren't thinking it.)) So why does everyone give him that look when he chimes in and finishes Shen Jiu's sentences? It's not that he agrees, he just sees where he's going with it! It's just that Shen Jiu is too predictable with his villain dialogue! (He's not.)
They are shockingly effective at shutting down their own and each other's rivals, with a sharp word or a veiled threat.
It's a good thing they always look so mad about it! The only hope their peers have is that they haven't ever deliberately teamed up...
...Yet.
