Ooh I'm hoping that either "Startin'" or "rainy day" have a dark, Japanese feel to them to suit the mood of Onimusha! (I've never heard any openings/endings for the Onimusha series before, so I don't know what they're generally like. I am playing Onimusha Tactics for Gameboy Advance right now, but of course GBA games generally don't warrant full scale vocal themes
).