catsister (elona)
The Younger Cat Sister is a hidden character from Elona. They generally only appear after reading a very rare younger catsister's diary item. As such, they are a rarer version of the Younger Sister character.
Aside from the obvious cat ears and cat tail, in-game, the main difference between a younger sister and a younger cat sister is that the cat sister has double the speed and one third the health.
Salient characteristics of the cat sister are blue hair, the aforementioned obvious catgirl features, hairpin, blazer and pleated skirt as if from a Japanese middle/high school uniform, and dark thighhighs.
Like most Elona characters, they are randomly named upon spawning, and Younger Cat Sister is just a class name. In-game, they appear as something like "Anita the younger cat sister".