My own mentee is a winter power holder and guild member! His name is Shoto Todoroki. I know some other capable and helpful people who are winter-aligned - my friend Rider, my quest partner Thoma, and Mr. Clavell who's a pokémon researcher -, but I don't know if they joined the guild. I can get you in contact with any of them too, though! I reckon Mr. Clavell is the most research-aligned; the others are all adventurers like me.

[And then there's Levi... but Hijikata wouldn't feel comfortable recommending that sour little man to anyone, least of all a mannerly lady like Faruzan!]