Kurodani Yamame A tsuchigumo youkai. Her ability to manipulate illness made her hated, and she was sealed in the Underground, but her bright and positive personality made her popular with everyone there! Can't seem to leave alone the shy Kisume-chan. Acts belligerent towards humans and seems to view them as prey.

Kisume A tsurube-otoshi youkai living in the Underground. Very bashful and always hiding inside her bucket. Loves Yamame-chan for always taking care of her! Falling from above and hitting humans on the head is a hobby of hers?

Kawashiro Nitori A kappa engineer and old friend of humans. Apparently bothered by Yamame-chan polluting the river. Normally shy with strangers, but this time she's going on a rampage with the power of booze!