Punch line: Rabura Chichibu

 A gal-style fishy spiritual medium.

Her name is a pun on "chichi burabura." "Chichi" is one way to say "boobs," and "burabura" is an Japanese onomatopoeia meaning "walking aimlessly." This reflects how she has the largest breasts out of the cast and doesn't really know what to do with her life.

Hakone-chan: Hakone

Hakone is a hot spring spirit who is in the form of a young girl dressed like a shrine maiden. She is one of 7 of Hakone's spirits.

Since she has been sleeping for a long time, she looks like a small girl. Specifically, she refers to herself as the "Master of the Onsen" (of Hakone Onsen).

Sleepy Princess in the Demon Castle: Aurora Suya Rhys Kaymin

The princess of the human kingdom. Kidnapped by the Demon King, she spends her days waiting for the heroes to rescue her. At least, that's how it was supposed to be...