Kylo? Fucking. Emo. Baby. Ren? Any H/Cs around their interactions? Or his opinions on what Hux is doing? Does Cal ever very specifically head-butt Kylo in the nose?
I’m answering this one first bc HOO BOY DOES CAL HAVE SOME THOUGHTS™ ABOUT KYLE RON
Cal finds him absolutely ridiculous and from their first meeting continuously finds ways to poke and prod at him. He thinks Ren’s temper is too quick, he’s an entitled brat, and his reasons for being in the First Order are shallow and pitiful.
He definitely doesn’t think Ren deserves the chance to become Supreme Leader (In fact, he doesn’t believe a force user should be the head of any functional government), and continuously needles him when context allows.
Oh, sure, when absolutely necessary he’ll show some reverence, but by the time he’s fully entrenched in the FO, he shares Hux’s opinions of Ren. He’s a sulking, spoiled child who takes his power and position for granted.
It doesn’t help that Cal despises him on principle bc Snoke’s original intention was to have Cal conditioned and then given to Ren like some kind of gift, an obedient second in command for him and possible apprentice, or even the start of the rebirth of the Inquisitorius.
Cal learns of this from Hux and his already low opinion of the Leader of the Knights of Ren drops even further at the idea of being commanded directly by him.
Of course, Ren is furious because Cal was supposed to be his, and Hux managed to snatch the last classically-trained Jedi out from under him. This colours a lot of his interactions with Cal and leads to Cal’s less-than-stellar opinion of him.
Ren finds Cal fascinating, especially in the early stages (Before Hux gets his claws sunk deep in the Jedi). His abilities are rare and extremely well-developed, he’s an expert fighter, and even before he’s cleared for sparring he demonstrates a deep knowledge of Jedi history.
Ren wants that. He wants to know everything Cal does, and Cal absolutely does not want to share any of his secrets.
Is there perhaps a time when they’re sparring and Cal decides “fuck this” and uses his psychometry? Yes. Is his reaction to this visceral and absolutely furious and directed at Ren? Yes.
Does Ren retaliate at a later date by using Cal’s psychometry against him (in a very uncharacteristic demonstration of tactical smarts)? Yes. Does this result in Cal with a scar and a deep distrust of Kylo Ren, driving Cal closer to Hux and leading to to a rift that splits the entire First Order in half?... maybe.
Kyle Ron is fascinated by Cal, but also painfully jealous and infuriated by his lack of respect.
Cal almost pities Ren, that he would sacrifice his entire family for power, that he is so conflicted but continues to make the wrong choices out of stubborn persistence.
But mostly he just thinks Ren’s an immature child.