OH BOY okay okokokok SO ill just go point-by-point

• if it is one (1) thing about kuguri that you have to take away from this answer its that he Does Not Talk Like Sakuma Rei From The Hit Game Ensemble Stars. KJHDFSKJFHSDK that is the biggest mistake anyone could make with his charavoice

other than that:

• kuguri is not formal with his speech hes really lax, teasing, etc but he wont ever say please KSDJFH this is like super important he is incredibly self confident and doesn't enjoy being "beneath" anyone. if that makes sense.
• his speech also isn't very complicated or dramatic in a casual setting. like he'll reference specific things (ie: liszt's pieces or the theory about the oyster shell), but the most he'll ever be is vague about something
• he addresses everyone in the cast by their first name even those older than him (the only exceptions being ev3ns/chief bc he has nicknames for them)
• kuguri doesnt like being told what to do (he straight up says so in ev3ns mainsto side a)
• kuguri is acutely aware of who interacts with him physically as well as when and how
• he can get really passive agressive KFDJSH he's very snake-like with how sharp and fast he is with being mean
• only stays in places if (1) he absolutely has to and (2) it interests him enough to stay.

ofc ill go into more detail when i inevitably post my kuguri brain vomit KJFHD i hope this helps anon if i think of anything else i'll follow up KDSJFH