Kyrin isn't the type to butt into the affairs of others needlessly, and he rarely initiates conversation by himself. He is, however, the type of person to fully commit to solving a problem once it involves him and is willing to help others even if he doesn't get anything in the end. Though it's partially out of his concern for others, it's mostly to put his mind at ease. He's also very bad against overly energetic and optimistic people, and usually ends up arguing with them while focusing on the negative, but he occasionally shows flashes of bright motivation and outward confidence when he finds something he can put his mind into.
Josh: Kyrin will find that there aren't many similarities between him and Josh, but that doesn't necessarily mean they'll end up fighting a lot. Instead, he would probably end up following up on his sarcasm at times while throwing a few verbal jabs at Josh himself, especially about that magikarp of his.
Dwayne: Kyrin's more conservative when it comes to relations between the opposite sex. He wouldn't really find Dwayne's actions acceptable, but at the same time, he wouldn't barge in between them unless the female is visibly distressed. All in all, while Kyrin would be the first person to call Dwayne out on what he's doing, he has no other problems with him, and holds a fair level of respect for him since he cares about his pokemon.
Rose: Normally it would seem that Kyrin would find some kind of relation with Rose due to their similar family background, but the similarity is only superficial at best, so it wouldn't advance much further from that. He would definitely enjoy poking fun at Rose for her physical appearance though, and he wouldn't hesitate on pointing that out upon their first meeting either. He's surprisingly fearless in this aspect, and he would likely continue doing so either way despite her protests.