Spoilers for Hiver
Holy shit, I randomly listened to the sample voices in the sound settings and realized they're all in-character comments about the game instead of generic random lines from the actual script. I'll have to go back to the previous games and listen to those too
Also they threw in Yuzuriha and Nerine back in there after their reveal! Last time I played a game with secret characters they were neither added to the voice settings nor did the "other characters" settings work for them.