Cozy Moments Cannot Be Muzzled

Pet and Ryo would get along like a house on fire. There's some culture clash but Ryo's super good at navigating culture clash by now! (And her attitudes toward hospitality and her own house are more Ugaro than Lau.) Her various magical abilities are unnerving but he can see and respect her deep goodness. Pet is likewise vibing with him immediately. (They also have lots to talk about regarding what to do when People Commit Crimes Against You But It's Complicated.)

Pet and Aras: Well, Aras would love her, obviously. I think she would also understand Aras very clearly, very quickly, and then he would be faced with another person giving him trust and sympathy. :P

Athelas and Aras... I think initially there's a lot of mutual wariness. If they get to know each other better, they're mutually appalled by each other's existence. (Although Aras would also be very willing to help Athelas with some of his Problems! But I do not think Athelas would want that.)

Athelas and Ryo: Ryo would have Many Many Thoughts about Athelas. The first ones would probably be oh he's weird and I think he's dangerous? Meanwhile Athelas is... wary but still reflexively mentoring and/or poking at him, because Young Person In Athelas' Vicinity! Also Ryo reminds him of Zero.

Zero and Aras: Somewhat stiff and wary, because they're both People In Power and they take that seriously, but I think they would respect each other. Maybe not a close friendship there.

Zero and Ryo: I suspect Ryo would have to Very Politely remind Zero to take him more seriously once or twice, but after that things would go well!

JinYeong and Ryo: Quick mutual understanding there in a different way than Pet and Ryo. JinYeong is pretty easy to fit in Ryo's frameworks for young warriors, even if he is 70-something. JinYeong appropriately judges Ryo's danger levels and his likelihood of actually being dangerous, and only pokes at him a little bit.

JinYeong and Aras: ...okay, you know, I think Aras would be delighted by JinYeong. He's cheerful and straightforward and very comfortable in himself, and the his violent qualities remind Aras of Ryo. Fun to have around! And I think JinYeong is Mostly Chill around Aras, though probably a little guarded and not bothering to hide that.

BONUS: Lord Sero

Ryo's first spoken words in Tuyo establish

He speaks darau

He knows enough of Lau customs to know they have a different age of majority

He WANTS to be accepted as tuyo

He assumes this strange Lau lord has enough sense of honor to be worried about people's judgment for taking a child as tribute