Going with the 2P as the characters' evil sides, I wanna see their chibi selves still being evil, inflicting horrible things on humans and possibly each other for fun, and their big-sibling/parent figures being very proud. "Awww, my little boy's dismembering rebels already! He's growing so fast!" I'm okay with just about any variety of gore, and enjoy the idea of nation-tans eating humans and/or drinking their blood (they're not human so it's not really cannibalism, hehe). Play for dark humour, please. Bonus inspired by Things Mr Welch Cannot Do; they lie down on a battlefield and make carnage angels.
2P/dark!ensemble, chibi nations.