Kanae — Ruka

If you saw "ruka kanae" as a (e.g., in fanfiction or shipping), it could be a typo or misordering of Kanae Ruka or two separate characters. Alternatively, it might be a misspelling of:

or

If Sumi represents the "safe harbor" of pure, uncomplicated support, Ruka represents the "storm." Sumi encourages Kazuya quietly; Ruka challenges him loudly. ruka kanae