Sorry if this offensive to anyone. Everyone comes from different backgrounds and experiences. Kanna's from a conservative Catholic upbringing with family members who were officers, whereas Rhina's from a hippie non-denominational background whose parents, particularly her half-Japanese mom, was harassed a lot by cops. In Act 4, we'll get to meet her mom :3 She's kinda sarcastic.
I plan to have fun with her, when she seriously enters the series (which is a long ways off!) Still, it's gonna be fun :D