A minor semi-hidden character in Elona, the Younger Sister can be found either in the hidden "Mansion of Younger Sister", where a younger sister merchant sells homemade lunches, (that restore Sanity that you might lose after casting magic while confused or fighting the Cthulhu Mythos-inspired enemies in the game,) or else by reading a "Little Sister's Diary", which causes a Younger Sister to appear in your party. (The latter is a reference to Chokotto Sister, where the main character gets a "younger sister" for Christmas from Santa, complete with a notebook/diary instructing her on how to be a good one.)
In game, Younger Sisters appear with random names, as in, "Anita, the younger sister". Because there is no single name, just the "class" name is used.
Younger Sister appears with green twin pigtails with yellow ribbons and a red dress. She's also often much shorter than most other characters in a work.