abarakasen
A severely emaciated version of Ibaraki Kasen, skinny to the point of her ribs being visible under her skin.
Its origin lies in the entry from Perfect Memento in Strict Sense about hermits, which describes them as usually eating only a few fruits and nuts, and being capable of not eating at all once they turn 500 years old. The name Abarakasen (肋華仙) is itself a pun between Kasen's nickname Ibarakasen (茨華仙) and abara, the Japanese word for "rib"; in English it would be something like "Ribarakasen".